The reason you use a boost referenced (1:1) or Rising Rate (anything more than 1:1) FPR is so that as you add boost the fuel pressure doesn't "appear" to be decreasing.
As you add boost the pressure differential across the injector gets less, so say you had a base FP of 43 psi and 10 psi of boost, your injectors will see a pressure differential of 33 psi. so what a boost referenced FPR does is adds 1 psi of FP for every 1 psi of boost, so when you are on boost your injectors will still see 43 psi of FP.
Similarly a Rising Rate FPR will add (in your case) 1.25 psi of FP for every 1 psi of boost, so your injectors will see a differential of 45.5 psi and hence will flow more when on boost. Rising rate FPR are kind of a work around for not having big enough injectors, or using the stock ECU with extra boost, they can be used to good effect with a custom tune though, so don't count them out for that either.