Hi, it is up to you whether you wish to sit for 2 SNAP test or for 1. If you sit for only one then only those scores will be considered. But, if you appear for two then consider the best result of yours as a final score. So, it is fine to just not appear for one exam. But, it is recommended that since you already registered for two you appear for both of them so that you get the maximum benefits for your marks. If you still have doubts feel free to comment. Hope this helps.