This thing with applying EAD 4-5 months in advance has really screwed me over in the last 3 years.
I have had 4 EAD's in 3 years because of this. Every time I applied the EAD 4-5 months in advance the USCIS has approved the EAD within 1 month and the had the EAD effective almost 4 months before the first EAD expired. This way my every EAD was worth only 8 months.
Plus the last EAD was totally useless, the third was expiring in Aug 07, but I got he fourth in June and now got my GC, rendering the 4th useless. Not that I am complaining but got frustrated.
Well i am not trying to make any point here, you cannot absolutely afford to delay your EAD renewal else you might have to stop working for if your renewal doesn't come in time. So 4 month is the right time, in this case you will get the interim EAD.
So just keep watching the processing time. In case USCIS is shelling out EAD's faster you can take a calculated risk.
neo