Your pressure differences are fine.
It (can) matter(s) quite a bit. According to the local guy who does injectors/tested mine, the opening pressure ("crack pressure")
coincides with injector leakage. One of mine opened way too early (about 8 psi too early and 'flowed' a ton more than the rest......and consequently dribbled profusely when the crack pressure threshold was reached on the way down.
3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ -
"930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe
Movie: 930 on the dyno