The Load that follows an IntervalMatch prefix should only have two fields: Lower bound and upper bound. And the field in the brackets should be the number that you want to match against the interval. You use F_MEDICAL_CLAIM_DETAIL when you should use [Incurred YearMonth].
I guess maybe I didn't totally explain myself. My goals was to just link on the Provider ID AND use interval match to find the proper record that the service date fit into , THEN take the field(s) I need like "Allocation_PCT" and make it part of the PROVIDER_FACT_TABLE. My intention is not to create or keep any additional tables just to join a new field(s) into the PROVIDER_FACT_TABLE.
If you use the three-table solution (in the script) I suggested above, you will be able to create exactly the table you want when you create the application UI. That's one way to do do it.
Another way is to join all three tables in the script:
Facts: Load ... from Facts ;
Allocation: Load ... from Allocation ;
Left Join (Facts) IntervalMatch (...) Load ... Resident Allocation;
Left Join (Facts) Load ... Resident Allocation;
Drop Table Allocation;
Drop Fields <List of fields you don't want>;
But this is somewhat risky: If a date belongs to two intervals, e.g. a date is the end of one interval and the beginning of another, you will get a fact table with too many records. But the three-table solution is safe...