Yes, which is why I just use the data as a guideline and let the rifle tell me when the load's getting too hot. I try to look at several sources for data using the same or similar bullets for the specific powder and get a feel for the average max published load and then carefully work up slowly and carefully. Every rifle is a different animal. My 257 Wby has yet to show any pressure signs at all, and I've had it as much as 2 grains over max published loads for a couple different powders. The Ruger 22-250 I had would sometimes show pressure signs before the published max load was reached. As for the Barnes TSX's specifically, I've never had any trouble with pressures with them with any load under book published max's for same weight bullets. I think that the ribs actually make the TSX "softer" to the rifling (I don't really know how to put it) than even most cup-n-core jacketed bullets, making pressures similar or less for a given powder charge.
Disclaimer: Approach max loads with caution, and if you exceed a published max load you do so at your own risk. I am meticulously careful with my load workups and know what I'm looking for for pressure signs. Your mileage may vary.
Mike