The macro you posted is incorrect.
Inorder to calculate the White Hit Crit Cap for rogue.
Out of total 100%
24% of your attacks will be glancing hits.
4.8% will convert into hit because of crit suppression mechanics.
To make it in maths it becomes
100%-24-4.8=71.1%.
Now remember till this point miss chance hasnt been included in it.
So 71.1% - Miss chance you have right now=White Hit Crit Cap.
White hit cap is 27%. Through that you can calculate the your miss chance you are having. You can also add up daranei hit as well if you want. I would say you should, because in raid usually you have racial hit as well.
This macro works as well:
/script DEFAULT_CHAT_FRAME:AddMessage ("Your crit cap for white attacks is "..(0.712-(214-GetCombatRating(24))*0.000305-(722-GetCombatRating(6))*0.000305)*100)
If you want to include heroic presence, add 0.01 somewhere in the equation. On second thought just subtract 33 (or 32.79 if you want it more accurate) from the 722 if you want to include heroic presence. While 0.01 does work mostly, if you happen to be hit and expertise capped it will give you a false number. Also you need to adjust the 214 and the 722 figure if you are not 5/5 Precision and 0/2 Weapon Expertise.
Courtsey:
https://www.mmo-champion.com/threads...-Cap-FAQ/page2
Feel free to read that forum, i suggest every new rogue. You will end up learning new theorycrafting stuff regarding rogues. I did myself as well.