Your irons are way nicer than mine, and mine aren't forged, but I've been playing the same crap set of Rams for 8+ years. I only get to play maybe 3x a month on average, but I hit the range a lot, and I haven't lost any distance on my clubs. I'd agree you need to try your current irons side by side on the same launch monitor with any new clubs to see how well the monitor is tuned.
@Zeph, are you sure about that? I see your point about V vs. square grooves only making a difference out of the rough, but the pros are only using very unworn irons. It seems physically possible to me that a really worn set of grooves could be rounded out enough to have less friction with the ball and create slightly less spin? Of course, I haven't found that to be a problem with my irons, but I've learned so much over the last 3-4 years that my distance has been steadily increasing, so it still seems possible that I've lost a couple yards from decreased friction on the club face but the swing changes I've made have led to enough increased swing speed to easily outweigh the couple yards I might have lost.