The specs on the TaylorMade P790 irons are NOT the same as the Ben Hogan PTx irons. The price difference is because the Ben Hogan's have a slower meter. In irons this meter difference is especially noticeable with lower end balls.
However, what you really should do at level 76 is get the your first "forever" wedge. People will argue that the Titleist Vokey SM7 wedges perform less well than other wedges. But when I peek into fmagnets' bag and find the level 78 and level 80 Cleveland wedges that were replaced by the Titleist wedges, I have to conclude that there is a reason. Start upgrading your wedges with the Titleists set. Then at 78 and 80 complete the set.
The Hogan"s are good irons and could get you through to the top Callaway sets or you could choose to wait for the level 85 Callaway's but that seems a long slog with starter irons.