Why does phone do this when I do this?

[dguidry12]

So I have a GS3 and I want to know why my phone behaves this way and should it behave this way.

 

While at work I have a lackluster 3g connection and a slight LTE connection so my phone goes in and out of data service. To prevent this I switch the phone settings to CDMA only so that I can pick up and maintain at least a less than decent speed and connection. However, when I make this switch my phone goes into EDVO mode and will not pick up an EHRPD signal at all. Id prefer the EHRPD signal because that seems a little better.

 

With that said is there a way that I can fix this and why does it do this? Very frustrating.

[Ascertion]

Ehrpd and evdo share the same 3g backhaul. Ehrpd is only there to hand off the transition to lte from evdo and vice versa.