Is there a weird system for measuring the diagonal? Reason i ask was i wanted to buy one of those pull up projector screens that are portable, and wanted the optoma with viewing dimensions 2030cm x 1145cm. which is 92". as advertised. But thats out of stock most places so i found the Sapphire SFL200WSFP listed as a 16:9 100" diagonal for only a bit more. Seemed a good enough deal. but everywhere i look lists its viewing size as 197cm x 111cm which is 89". am I missing something?