Part of that ODD74 thread includes a post of an excerpt from a Chainmail example Gygax published in an old wargaming newsletter. It specifically said that 2 units locked in melee did continue their melee into the next turn.
[there was no way to include the screenshot I took in this comment, so here's the post]
{this part from the poster}
Gygax's example of a Chainmail melee from the Great Plains Game Players Newsletter #15 (Feb 1975), newly uncovered by badger2305, appears to support that when a melee continues, it does so in a melee round in the next turn, rather than continuing in the same turn. Note especially the bolded part.
{end poster}
{from Gygax}
Let’s take a peek at a likely example.
Assume 30 Foot Sergeants (elite) are attacked by a unit of 10 Heavy Cavalry. The horsemen come thundering down upon them, and immediately the poor devils must check morale, needing an 8 or better to stand. Thus the Foot must turn and flee about 6 times in 10. Assume that they stand and fight. The HC get 3 dice per figure, plus 1 die for charge impetus, or a total of 4 per figure, with 5’s and 6’s killing. The average kills would be about 13. The HF get 1 die per 4 figures, with a 6 killing. There is no logical way the Foot could fight with all 30 men, but let’s be generous and allow them an average kill based on 6 dice, 1 horseman. Time to move on to the Post Melee Results.
Base score for the HC is 9 x 9 = 81. Assume they roll a 3 (low average) to multiply times their kill bonus, for a score of 12 x 3 = 36 + 81. Their total score is 117. The base score for the HF can be interpolated as a “Morale Rating” of 6 due to Elite status times the number of their survivors: 17 x 6 = 102. They receive a bonus for having the greater number of surviving troops, 8 in this case, so their total is 102 + 8 = 110. A doubling of the difference (7 in favor of the HC) indicates that the HF barely managed to hold, and
<this section was bolded> a regular melee round would ensue next turn <end bolding>
(in which the poor infantry will really get butchered). Had the HF been a bit fewer than 3:1 over the cavalry, or had they not been Elite, the horse would have easily broken them and continued their charge. In the above example 1 fewer HF would have meant a success for the HC, in fact.
{end Gygax}
[end of quoted post]
I believe the rule covering continuing charges is meant to cover only that specific corner case. Given that retreating or routing units would get their full movement or 11/2 movement, a charging unit catching them a second time would be infrequent. (I've always found it strange that defeated units get movement matching or exceeding units on good order.)
This is fascinating! Great work on "rule diving" as well as the must-have of play testing!
Saved for future use!
It would have made more sense for me just to link the post
https://odd74.proboards.com/post/240710/thread
Part of that ODD74 thread includes a post of an excerpt from a Chainmail example Gygax published in an old wargaming newsletter. It specifically said that 2 units locked in melee did continue their melee into the next turn.
[there was no way to include the screenshot I took in this comment, so here's the post]
{this part from the poster}
Gygax's example of a Chainmail melee from the Great Plains Game Players Newsletter #15 (Feb 1975), newly uncovered by badger2305, appears to support that when a melee continues, it does so in a melee round in the next turn, rather than continuing in the same turn. Note especially the bolded part.
{end poster}
{from Gygax}
Let’s take a peek at a likely example.
Assume 30 Foot Sergeants (elite) are attacked by a unit of 10 Heavy Cavalry. The horsemen come thundering down upon them, and immediately the poor devils must check morale, needing an 8 or better to stand. Thus the Foot must turn and flee about 6 times in 10. Assume that they stand and fight. The HC get 3 dice per figure, plus 1 die for charge impetus, or a total of 4 per figure, with 5’s and 6’s killing. The average kills would be about 13. The HF get 1 die per 4 figures, with a 6 killing. There is no logical way the Foot could fight with all 30 men, but let’s be generous and allow them an average kill based on 6 dice, 1 horseman. Time to move on to the Post Melee Results.
Base score for the HC is 9 x 9 = 81. Assume they roll a 3 (low average) to multiply times their kill bonus, for a score of 12 x 3 = 36 + 81. Their total score is 117. The base score for the HF can be interpolated as a “Morale Rating” of 6 due to Elite status times the number of their survivors: 17 x 6 = 102. They receive a bonus for having the greater number of surviving troops, 8 in this case, so their total is 102 + 8 = 110. A doubling of the difference (7 in favor of the HC) indicates that the HF barely managed to hold, and
<this section was bolded> a regular melee round would ensue next turn <end bolding>
(in which the poor infantry will really get butchered). Had the HF been a bit fewer than 3:1 over the cavalry, or had they not been Elite, the horse would have easily broken them and continued their charge. In the above example 1 fewer HF would have meant a success for the HC, in fact.
{end Gygax}
[end of quoted post]
I believe the rule covering continuing charges is meant to cover only that specific corner case. Given that retreating or routing units would get their full movement or 11/2 movement, a charging unit catching them a second time would be infrequent. (I've always found it strange that defeated units get movement matching or exceeding units on good order.)