I agree with Thomas & Bill with the caveat for Ratty Mouse that contrast adjustment, when using a lab for prints and scans, is simply a matter of telling the lab what is expected.

Even if you self develop and send your finished negs to the lab, the lab may then "correct" the print contrast and exposure to "their sensibility" rather than yours.

Ratty Mouse until you have your lab try to reprint the negs in question to your preferences you don't really even know if you need to expose differently to get more shadow detail.