On my visit earlier this month at Epcot I'd missed one of my Tier 2 FPs, and used my other Tier 2 FP and my Tier 1 FP. When I went to a FP kiosk to try to get another FP I think it would only let me switch my missed Tier 2 FP to another Tier 2 FP (although according to the Lines app there were still some Tier 1 FPs available).