That's actually not bad. 40 C at idle and 55-60 C under load would be the broad targets, and one CPU will typically run a little hotter than the other.
If you can get CPU A down into a similar range as CPU B, then the hack works 100%. On the other hand, as things stand, 70 C is nearing the maximum tolerance, which is somewhere in the region of 80 C or 180 F. It'd be worth applying new paste and maybe running a thermal recalibration.