Manifold Vacuum Advance what am I not getting?

I must be missing something. U say the motor wants the base timing at 42*. So what do u have when the mechanical comes in, then when the va comes in? My guess is around 70-80*. Get yourself a good timing light. And maybe someone that knows how to use it. Are u timing on number one for sure. Maybe the damper has slipped. Or your terminology is wrong. Base timing is just that. Add in your mech at 15-20 then your va at 15-20 so your around 80*. Can’t work no way no how. Kim