I am using the slower RNG Manip which is saving and quitting near the Mart, i am doing all inputs correct with Pressing the A button correctly too. The nido encounter is in the correct space (Bottom Right patch) and is level 4 but every time he has 17 HP!?

Having the same problem here - every time the stats are 9/8/10/8 (I assume this is the 00F0 DV Nidoran, but I've restarted 3/4 times and resaved multiple times on each run and get this Nidoran consistently.)