I had a quick look at it for you and compared it to the Google Maps satellite image, and I think I figured out what's going on. The ground markings have spots like 48A, 46A, 46B, and so on, but there's no way to list the parking as such, so if you're seeing something like A46, that would be for spot 46A. B46 would be for spot 46B. Gate 77, for instance, would just show up as gate 77 without a letter. Hope this helps.
That's only valid for FSX or P3D. In MSFS, the parking naming system has improved A BIT (still limited), because there's a "Prefix" parameter which has been added to the parking name so yes, you CAN have 48A, 46A, 46B. Provided, of course, whoever made the scenery *used* that feature in the first place.
Still, you can't name terminals by numbers, they can only have "GATE" + a letter so, something which in real life is "Terminal 1 Gate 48A", could be named either "GATE A48A" or maybe GATE 148A" with the 1st digit representing the Terminal Number.
Of course, GSX with a custom airport profile, can fix all of this, and offer realistic naming, provide whoever made the profile used the Python customization feature, which allows renaming and regrouping of the parking, at least how they are presented in GSX.