FYI - Buick did a "sneaky thing" in my opinion. The injectors in a turbo Regal tend to flow 28.2 pph with the stock regulator. Therefore, everyone refers to them as 28pph injectors. Fast forward two years and the LC2 motor shows up in a TTA...and the chip shows 30.x pph. As such, lots of people believe the TTA injectors are different...they aren't.
The TTAs recieved a fuel pressure regulator that runs at the "industry standard" of 3BAR (43.5psi). Note that whenever you look into buying fuel injectors, the pph rating they have is when they see 43.5 psi pressure. The turbo Regals only ran something like 38psi. So the 30 pph injectors were rated as 28pph on the Regals and 30pph on the TTAs.
Originally, all Thrashers were simply made for the "industry standard" 43.5psi of fuel pressure. Enough requests came in for a chip that gives the Thrasher features to someone with the stock fuel pressure regulator, thus, the 92-28.
Perfectly clear now?