The long wait times are normal. With R10/HR15 swaps (older mpeg2 boxes) and NFL season starting/started there is generally a 2-5 week lead time.
TBH I think it has more to do with the amount D* and install companies have cut back on what they pay techs and the lack of time off they have been giving techs.. so many long timers have quit. (as well as overwhelmed new techs) Plus D* generally gives fulfillment companies 20% more jobs that they can handle to balance out LOS issues/Door Tags/Unable To Locate issues. With their new LNB that eliminates many LOS issues, that 20% has not been a safety buffer but a burden now.
So yea if they give you a 4 week lead time, its because they probably cant handle more before that, but by bypassing that system (there is generally a 48-72 hour before each or teh other gets changes) and going to the install company to get a earlier time or via web.. you are just further contributing to the "late shows" or no shows for that day since D* filled it and someone else added to the already loaded day. So if you get a 1 month date and get it moved up to 2 weeks, do not get pissed when your tech is late that day.