You shouldn't start at the max charge for a different bullet. However, the XTP IS a jacketed hollow point bullet, so published data for a different 200 gr jacketed bullet is a good starting point for your XTP load. But since you're looking at data for a different bullet, you should start at the minimum load and work up. If you only have a single powder charge instead of a minimum to maximum load range, then you should start 10% under the load for the different bullet.