Unlocked LG G4(US991) Network Mode setting

[do69what]

I just bought an unlocked LG G4 (US991) model and put my cricket Sim card in. I put the APN settings in from cricket's website and saved them. My question is what should the "network mode" really be. On "Global Mode" I'm able to get calls,text and I get 4g lte data. When I switch it to "GSM/UMTS" mode I can call, text BUT data is only at E speed not 4g lte. Shouldn't it really be on "GSM/UMTS" mode not "Global"?