Couple of things I'm not understanding here;
The examiner hands you a temporary certificate good for 120 days and you can exercise the privileges of the new certificate or rating immediately.
So I'm not sure as to why you are upset about the wait.
I also think the difference in wait time between the two ratings was more the luck of the draw then anything else.
IACRA applications are printed out in Oklahoma and then manually processed.
Your DPE may have saved up a couple of week's worth of check ride paperwork before mailing it in, perfectly normal since your temp is good for 120 days and you get the privilege or exercising your earned license right away so what's the rush for them to mail it in?