This is a quote from an email conversation with Sprint Customer Advocacy Team for the Yuma area.
"What I was informed was, your area (Yuma, AZ) is heavily loaded/capacity constrained and is in need of a permanent NGN (Next Generation Networking) solution. The Local RF team has already proposed a NGN solution but they have to get it through the funding process (not an easy task). Since there are a lot of moving parts, we don’t feel comfortable sharing an ETA for this project. However, as the NGN proposal goes through the funding process, the local teams also escalated the funding for a 2nd LTE carrier to be deployed to all the applicable sites in the area (including PH12AL015). This 2nd LTE carrier upgrade is tentatively scheduled for some time in April 2016 and should help provide capacity relief to the area."
I guess we won't see much movement down here for now..