Hi joe scafone,
You can see in post #3 here that there is some variance in standard sizing for mattresses but in general plus or minus 1" (sometimes 1.5" for custom sizes) would be the norm. The Sealy size tolerance listed on their site here is +/- 1/2" to 1".
IMO … your mattress is clearly out of spec (and there are certainly others who have experienced this as well) and I would ask to return it for a mattress that was within the normal size variance for a king size.
The size you received is closer to a king size in Japan (which is 194 cm x 195 cm or 76" x 77") than it is to a North American king size.
Phoenix