Split form total not always showing (1 Viewer)

I have a split form with a sum of totals in the form footer. The total shows as long as the fields are filled have data and as long the cursor is not moved in to the next bank field of a new record. How can I get the total to always show and calculate properly?

Offhand, I've had better success with total fields by having their values assigned via VBA, and then just re-running the totals calculation when a record is saved.

Then again, I'm dealing with tables with millions of records, which in turn tends to result in significant lag if you're not careful.