Why do you think the two items have to match?  (I don't think there's a diagnostic for non-matching.)

As you pointed out, Sch G Part II lists only events with gross greater than $5,000.  990 Part VIII Line 8b lists all events.  When you have an event with gross under $5,000, the two lines would not match.

The instructions mention matching only for the gaming (Part III) - to be matched to Line 9.  I don't think there's an expectation or requirement for Line 8 to match to Part II Sch G.

Spoke to Lacerte support and realized the only way to have this match is to combine the events all on to one line.