Did you click on the links and look at the "Topics Covered" by each book?
The two "single variable" versions (early and late transcendentals) cover the same material, but in different sequences. Some schools prefer one sequence, some schools prefer the other one.
In the "combined" versions, chapters 1-10 have the same material as the "single variable" versions. Chapters 11-15 are multivariable calculus.
The "single variable" versions are for the usual Calculus I and II courses in colleges and universities. The "combined" versions are for Calculus I, II and III.
High schools usually have only single-variable calculus, but colleges and universities have both single- and multivariable calculus.