Brother I have no idea regarding EER, as HVAC is not my field, however, to me, the one available in stock right now just seems fine and worth buying. Secondly, the data available here for local products on local websites, is not 100% accurate.
If some product is out of stock, it can also mean that it is discounted, or might discontinue in the near future.
IMO, it is always better to go for and buy running items and models, i.e. the Brands and their products which are "IN" in the market.