Helicopter pilot reported not verifying the weight and balance information in the aircraft manual prior to flight and flew the aircraft in a non-airworthy condition.

Narrative

I was on duty; day pilot; [at] ZZZ1. I was asked to stay in service and fly to ZZZ to complete a maintenance flight; ROC (Rotorcraft Operational Check); on Aircraft X. The aircraft needed the ROC for main rotor rpm in autorotation. The aircraft was supposed to be 100% finished with all maintenance and ready for me to fly upon arrival at ZZZ. I arrived at ZZZ and first briefed with the mechanics on the work that had been done and what we needed to do. I did a preflight of the aircraft. After the preflight I went over the logbook with the mechanic; the aircraft had all the maintenance completed and the last thing it needed was the ROC. I used [software program] on the iPad for weight and balance and a flight release. We flew the aircraft; it was within limits on the ROC; completed the flight; documented the ROC and I left. Yesterday I was informed by Name that the aircraft had been weighed and the weight and balance was not correct and did not match what was documented in [the software program].I made the assumption the aircraft was in compliance and did not verify the weight and balance in the RFM (Rotorcraft Flight Manual). I was on duty; it had been a busy day. In the future it would probably better to have a pilot dedicated to the maintenance task and not on flight duty. For myself I need to go over all documents to verify compliance.