I looked at the Laticrete web data sheet, and although it talks about using 4237 and the 1500 grout when a colored mix is desired, I can’t find anything about this mix complying with ANSI A118.4 Latex Modified Thin-set standards. I believe it has been tested to make sure it has the strength requirements for bonding, but has not been tested for compliance with the other parameters of 118.4 (i.e. opentime, adjustability, sag, inital set, etc..)