Right, and for this first part of the API 610 report (page 2) it's simply multiplying the Table 5 factors by the 2.0 modifier.

For example, the Suction Nozzle in Load Case 1 has an Fx of 1,729 lbs. On page 1, the allowable is 700 lbs, so the ratio is 2.51 and it fails. On page 2, the modified allowable is 1,400 lbs. The new ratio is 1.26 (still exceeds the modified allowable) but it says it passes.

The way I read F.1.2.a is each force/moment should be lower than this modified allowable. Then the next step is calculating F1-F5 later in the report for the combined loads.

What am I missing?