I've been shooting Potra 160 in 35mm at ISO 800 and let the lab do only +1 push development, meaning development at ISO 320. So underexposure was comparable. I took shots of a music events and some on an automotive exhibition. The negs came back a bit dark, but nothing that a good scanner could not handle.

Your shots will probably be fine even if you do not compensate for it in development.

Christian