I typed it pretty clear. He knew what his strength was whenever he fought him last before the injury. By never fighting him again after the injury means he doesn't know what his strength is.
Any other pov of looking at it and well get in a pointless debate.
if that is what you meant then let's really look at the majority of people Mihawk fought at the war.
Luffy - fodder to you
2 okama swordsman - fodder to you
some other nobodies who approached his path, marines or pirates - fodder to you
Buggy - fodder to you
Crocodile - fodder to you (stronger fodder but still much more weaker than Mihawk to you)
1 slash only at WB/ Jozu - never did that again
Vista - who you see as a much lesser swordsman
If I forgot some1, my mistake.
Either way, you are saying these opponents makes Mihawk miles ahead of Kuma for beating the SH's and being 1 of the key people to take Oars Jr. down. Other than Luffy a bit and Iva. Like I said before, I'm going by the Kuma with a personality. That Kuma wasn't at the war, so once again those other examples are the only 1's yet they leave lots of questions of his full abilities.
As for the iceburg cutting feat, Kuma 'ursus shock' reducing that whole huge island of TB is also 1 of the best destructive feats in the manga