You can offer any theory you want too... But given the results gained by just switching batteries at least my theory offers some tangible proof.
If you buy a new fully charged wet cell, that might also make the bike hot start easier.
Temperature is the culprit, right?
Where's the biggest temperature swing, inside the engine.
Here's some physics:
Permanent magnets loose flux density as heat increases.
Heat also lowers the permeability of Air.
It takes a higher flux density to excite a heated coil.
Inductance of a coil increases with heat.
Add all this physics up, and a moderately performing battery may not spin the motor fast enough to get a strong enough pulse from a more inductive coil in a less permeable environment from a weak flux density generated from .030"+ distance.
By moving the pickup coils closer to the magnet, you compensate for the negative changes in flux density due to temperature ... maybe ... just sayin'.
And the closer you get to the passing magnet, the sooner the pulse reaches trigger level. This would effectively advance the trigger, therefore, the ignition.
Of course, this is all just my opinion. except for the physics parts.