If your talking about Cynoscephalae then you need to watch the link i posted and listen to it. At no point did the Romans retreat to better ground, The two sides met not intentionally, skirmishes battle for the high ground, Romans driven back. Philip moves some of his phalanx's that are formed and ready to the higher ground and the Romans begin their attack, Macedonians drive them back. Other roman wing attacks the not fully formed up Macedonians on Philips opposite wing and likewise drive them back. One of Philips wings is driving the Romans back and therefore pushing forward the other is being driven back thus creating a gap which the Romans exploit.
Also your numbers are ridiculously high the Macedonians, i have found the following range of figures:
Both sides were roughly equally matched, mustering about 25'000 men each. -
http://www.roman-empire.net/army/cynoscephalae.html
When Flamininus began his march to Larisa he had under his command about 32,500 to 33,400 soldiers. Philip had about 16,000 heavy infantry in phalanx formation, 2,000 peltasts, 5,500 light infantry from Illyria, Thrace, and Crete, and 2,000 cavalry for 25,500 troops overall. -
http://en.wikipedia.org/wiki/Battle_of_Cynoscephalae
Flaminius, the Roman general had around 30,000 soldiers. Philip V had approximately 22,500 forces. -
http://rtw.heavengames.com/history/b...ae/index.shtml