lt1 opti spark distributor

this may a weird problem,i have a 1996 buick roadmaster with the 350 lt1 eng and my opti spark bit the dust.i replaced it,actually twice because i got a bad one.after replaceing the second one i put my scanner on it to ck for misfires etc,and found my timing to be at idle -17 deg and when i accelerate to say 3000 rpm it goes to -39 degs.the car is deffinately not running at this timing because the car performs perfect,starts normally and when at wot on the on ramp,or passing,no misfires and perfect acceleration, plenty of power.my question is,did the opti spark cause this or is my ecm in some kind of coma.  

I've always had very unreliable timing readings with my '94 Formula as well.