The measurement may not be exactly the same on an XP, but my measure of a Step-Thru, from the top of the seat (receiver) tube
to the top of the steering (receiver) tube, center to center, is 25.75 inches.
The "working" or practical distance from seat to handlebars will vary, of course, with the height setting of either.
Maybe some XP owner will see this "boosted" post, and give you an XP-specific answer ;-)