From my understanding, V2 is also a margin above Vmca, so if V2 were say, 150kts, then flying 145kt means you are eroding your protections for engine failure - would probably need a lot more rudder, and some bank and have to get the nose down in a bit of a hurry.
...and if your perf fig's were indeed under-calculated, you might actually be a lot closer to Vmca and Vs than what you think...?