Sparky66;
I would think that they would be regardless of the tab. First the circuit is a Edison 3-wire, one neutral. red and black going back to the panel to a 2-pole breaker or two single poles with a tie-lock, the tie-lock because they both go to the same strap or yoke.
By removing the tab, now you have 240 volts at the receptacles, since it is a duplex, with two seperate neutrals. Yeah you are right I dont think they would be parallel, but the problem if ther are two seperate breakers then that would create a problem of safty. and one breaker could be off misleading the electrician into thinking that the receptacle is dead when its still hot, thus the need for a 3/c with a tie-lock on the breaker and no split neutral. IMO thats asking for trouble.