CP is a useful, but incomplete, analogue for what you are really interested in. Met, Lys, Thre, Tryp. The U.S. tends to use an excess of "cheap" protien to hit those targets. The best E.U. feeds can provide similar Met, Lys, Thre, Tryp numbers at lower total CP thru more effective suplimentation.
That's the general rule.
More specificaslly, yes, the Kalmbach line of feeds is pretty good, better than many, and at a not unreasonable price point. I don't use it myself, but many BYCers do with satisfactory to good result, and as indicated above, its nutritiotional numbers are better, typically, than many others at similar price point.
That said, many *but not all* Kalmbach feeds are whole grain. If you feed whoile grain, you SHOULD feed as either wet mash or fermented feed, to ensure the flock gets the fines.