ya, usually I 140 gets declined, coz of the financial situation of your sponsor, like their asset, cash flow, labor cost and so forth. if I 140 is strong, and visa number is available, you should discuss to your lawyer about filing your 140 n 485 together. and you are right, they dont give you the time frame, just to be in the safe side. but even legally, USCIS is suppose to make a decision about green card in 3 yrs.