Discover will report a balance different than the statement if there's been a change, but the report dates are always within a day or two of the statement. You can even ask them to do an off cycle report if you've paid the balance down.

NFCU seems to report the statement balance on the statement date.

Wells Fargo seems to report the statement balance on the statement date.

Barclaycard reports the statement balance a day or two after the statement date, regardless of newly posted charges in that additional day or two.