Assuming PGMAW is synonomous with Pulsed Mig--GMAWP (love those acronems) It's reasonable to see why it's called out.
A 72' dia. cap is a lotta milege for GTAW. Especially if you have alot of them to do. The Mig Fill passes are economical, with what, about a 10x deposition advangate over Tig?
The SA-240 is a 300 series stainless I recall, but no super special heat input sensitivity to require GMAWP over Traditional Spray transfer unless material thickness is below 0.125 in and your worried about burn through. But your issues being lack of fusion suggest that at least a little more heat wouldn't hurt. The only other real advantage to GMAWP is the ability to get a spray transfer weld out of position. If your operation has this requirement than thats another reason.
What type of pulsed GMAW power supply are you using?
Is your pusled mig operation manual or automated?
Is your pulse equipment synergic?
Groove or Fillet?
Material thickness?
There are about 4 generations of Pulsed Mig technology out there and each generation has specific parameter issues to be dealt with in order to get good production..... However, some older GMAWP power supplies were never able to perform as advertised.