If you are using an incident meter and a little instinct in regards to SBR, you are fine at box speed. People say to overexpose as a matter of course with C-41 film, but I don't like the results, personally.

But C-41 can definitely survive a mere 2/3 stop of overexposure without an issue. You will just find your proofing and printing times to be a bit longer than normal.