If your First Block includes RECs from both Size Classes, you are required to submit two Bid prices, one for each Product (i.e., one for RECs from the Small Size Class and one for RECs from the Large Size Class). These Bid prices will be evaluated separately.  It is not the case that the entire block is evaluated on a blended price basis.  Thus, it is possible for the evaluation of Bids to select the portion of your First Block for one Size Class and not the portion from the other Size Class.