Sony Ericsson :: C905a Would Debranding (AT&T) Cause Phone To Loose Reception Strength?

I recently debranded my C905a and I want to know if anyone knows for a fact that if by doing so I have reduced my phone's ability to mainain a decent reception signal. If I remeber correctly, I had the same problem before I debranded. I've called Sony Ericsson about the low reception strength and they told me that it was a network problem. I know that is not true b/c before the C905a, I was using a Nokia 2610 (a cheapie until I could upgrade) and that phone always had a signal virtually anywhere and I can count on 1 hand how many dropped calls I had using that phone. I do live out in a semi-rural area but, my mother has a Nokia 6555 (I live w/ her) and she does not have the problem with dropped calls like I do. But, w/ the C905a, I have to put the phone on speaker 3/4 of the time b/c when I put the phone to my ear, it simply looses all reception. The closer to the city I get, the reception problem becomes less an issue.