Why is the height difference weird? Do you know how to read tyre sizes?
The profile is a percentage of the width. So if you're sure you have 70 profile (seems odd for 265's, they are normally 75 profile).
then:
235/70R16 = 28.95" tall
265/70R16 = 30.61" tall
265/75R16 = 31.65" tall