With a balanced system, all devices (whether receivers, DVRs or DECA adapters) would experience the same reduction in signal. Wasting signal on terminators is a negative (though it is less negative than not having terminators at all).Wouldn't those same numbers you just quoted affect any receivers/dvrs connected to a sws8?
As is often the case, splitter insertion loss is in no way unique to DIRECTV SWiM systems. Because of the two-way nature of DECA, the splitter loss is higher than with most other systems.