It's only "twice" as much if you have twice the solenoids, which to my understanding, you don't. It would appear you have one nitrous and one fuel solenoid, with T fittings, feeding a pair of plates.

So while the single 52 jet is roughly 100hp on a single bar plate, depending on solenoids used, when you double that jetting, while still flowing through only one solenoid, it only makes about 50 more hp.

These power outputs also change depending on the nitrous solenoid used. Given the same jet, power levels will be different with powershot, cheater and pro-shot solenoids. The number on the jet is just a number. What matters is what it flows and that depends on the components used