Award Frustration

I have been pricing a US-Asia-Africa-US award redemption and get reasonable choices in J (including Singapore Airlines) when building it as three one-ways. However, when I try to put it together as a multi-destination trip, I get completely different options (and very poor ones, at that).

Question is...if I call in, will an agent be able to piece together the exact flights I'm seeing as one-ways and get it at the free stopover rate (120K total)? This is very frustrating.