Controlling VSIFT selection in BC

I'm working on tweaking a process in BC18 (On premise). Part of the process uses a Query object that is summing "Warehouse Entry" records. I've isolated the issue to the VSIFT index it uses to calc that sum.

The 2 indexes of concern are Key5 and Key8. Both shown below. The process is summing "Qty. (Base)". The query is filtered on all the fields in key8. Unfortunately, all those fields are also included in Key5. So BC uses Key5. Not surprising, this is how VSIFT has worked for years.

If I drop the query into T-SQL and run it using Key8, the result is better than a 50% improvement. I'm looking for how I could get BC to use key8. In NAV, I could simply disable the SIFT maintenance on Key5 to accomplish this. Not an option with BC.

Any thoughts?


key(Key5; "Item No.", "Bin Code", "Location Code", "Variant Code", "Unit of Measure Code", "Lot No.", "Serial No.", "Entry Type", Dedicated, "Package No.")
{
SumIndexFields = "Qty. (Base)", Cubage, Weight, Quantity;
}

key(Key8; "Location Code", "Item No.", "Variant Code", "Zone Code", "Bin Code", "Lot No.")
{
SumIndexFields = "Qty. (Base)";
}