If a multipass weld is required to produce the required weld size, it seems unlikely the weld you describe would have the required throat. Your description would indicate the weld is concave thereby resulting in an undersized throat dimension. It is also possible that the legs are too long to measure with a standard fillet gage. You may have to resort to making a gage with the appropriate throat dimension and adequate clearance for the fillet weld legs.

As the in-house inspector, you do not have to base your decision solely on the code requirements. There are workmanship issues that are not addressed by the code. The code provides the minimum requirements that must be met. You can impose more restrictive requirements if the issue relates to workmanship. Basically, if the weld doesn't look good, but it meets the letter of the code, it can still fall below "good workmanship" practices.

Envision if you will a full size single pass fillet weld. Then the welder adds an other bead right at the toe of the full size fillet weld. The weld meets the size requirements, there is code requirement that has been violated, but the weld looks like a goose just crapped on the joint. That's a workmanship issue. The inspector would normally require the welder to remove the excess weld for the simple reason of aesthetics.

Best regards - Al