The ONLY offset setting in GMRS, when used, is +5 MHz. Most GMRS radios will handle that. Ham radios, on the other hand, usually need to be told what offset to use, especially if set to xmit out-of-band. Even in-band ham repeater offsets vary according to which band they're operating in and what region of the country you're in.
FYI/FWIW, a repeater's output tone is only useful if you're getting interference on the repeater's output frequency OR there is another repeater (or repeaters) in the area on the same frequency pair. If the repeater's output is weak, having that tone detection turned on can, per my experience, prevent you from hearing said repeater, as scratchy as it may be.