Regardless of using a portal server to lvl weapons isnt the problem and MOST cheaters aren't over lvl 200 currently.
Since from mid Dec 25 to now S2 you'll find 98% cheaters are all low lvl accounts with insane scores( i do acknowledge that not all low lvl players are cheating) . For instance recent games I've seen lvl 4-70 getting scores from 75-1, 176-2, 236-1 and so on also with names that need reporting etc ..i cant name names but all very rude and to top it off a lvl 7 with a name to a cheat site,,,,yes """"""""""""".com is his name ...
Being level xyz doesnt mean a thing( tho ZSL is 2043 yestrerday) if you mastery a few weapons on each is all you need as being 200 , 500 etc isnt the issue its EA allowing hacks etc to be used as the anti cheat is doing nothing..
Though to be fair soon as its patched the hack sites re work their code and people buy a new account to cheat hence the Low lvl players..
Im quite high level but i grrind the weapon of choice to lvl 40/50 then move to next weapon. So far out of the new DMR LMG and Assault weapons. Im 50 mastery on DMR , 40 mastery on LMG and 38 mastery on Assault and thats from friday to today...so its not hard to level especially when xp weekends etc...