1050 is about max for K24 and is what my car does and gets to 21 degrees timing, you? So I must be there to lol, seriously that dyno chart I don't understand the numbers to what you said, looks like 350 bhp to me @ 1.4-5 bar of boost, you have some PID work to-do though on your boost..
20-21could be in high rpm. 261kw is 354hp. Its not bhp as in crank. Its wheels
This was with 1.4bar max. Dont worry about the boost. Its rock solid. Jagged edge torque curve was because it pulled timing quite a bit due to iat. Dyno fans cant produce 150+km/h wind. I tune on highway always so on dyno performance suffers.