CoE of float glass
I just can’t help being pedantic here. The CoE of some float glasses is in the range of 82 +/- 3. So quite a big range. Also some is made in the region of 90. As the manufacturers do not care what the expansion is, there is no way of knowing exactly what a particular manufacturer is doing. Minor changes in the mix of materials will affect the coe and they just don’t care.
In any case, you are right that the float glass will not be compatible with any other glass, and often not with itself if it comes from an other batch or manufacturer.