In OTL, Lee's order to Ewell was to "carry the hill occupied by the enemy, if he found it practicable, but to avoid a general engagement until the arrival of the other divisions of the army." If "practical" becomes "at all costs" the orders contradict themselves.
Ewell could have tried attacking immediately, but Rodes and Early's forces had been in heavy fighting. They were tired and hungry, disorganized by the day's events. He has to cover his left flank against possible Union reinforcements. He has to cover his right flank because AP Hill had made it clear he could not support Ewell attacking. Ewell would have to commit forces piecemeal and likely get them destroyed piecemeal.
The alternative is to wait till Allegheny Johnson's troops arrive at nightfall, giving the rest of Ewell's forces a little time to rest and get reorganized. That would mean a night attack. One was attempted with Johnson's forces in OTL, they ended up fleeing. Johnson supported by Early and Rhodes probably would have had less brittle morale, but the number of ways a night assault can go wrong are rather large.