Academy.fm - The Basics of Mastering in FL Studio 12

It's not that bad but in the end if you want to release your album or song on some label they will demand their own producer to master..

as a DAW it's really great. The reality is.... yes, the plugins are sooo sooo outdate... the compressor still doesn't have a GR meter or indicator since 2006. But this guide more than HOW TO MASTER it's how to know your tools and an idea of workflow for nice basic mastering.

I'm a mastering engineer. I master in FL since 2015.

Not to come at you bluerover, but I have heard this before. I'm a long time user of FL (after trying most other DAWs, it just fits my workflow the best, ) and I agree as so far as it isn't the best DAW to master in *if you use the stock plugins, which are still better than many DAWs.
The reality is, if you use third-party plugins, it really doesn't matter what DAW you use...unless the plugins suck as well. All DAWs are becoming more and more alike with every release, mirroring styles, layout, abilities, etc., of other DAWs; most will be identical soon enough.
This coverall statement is typical of FL mythology. I have heard that FL has "...an engine that is only about one-tenth as powerful as Logic or Reason's," (unsure how some guy fabricated that eXACT statistic,) that FL is "...only worth buying if you make EDM," "Phasing happens more often in FL," and "...is nearly impossible to correctly gain stage in FL." (All mentioned in "professional" tutorials.) The last really confuses me, seeing as how I have an easier time with that in FL than most.
And I'll skip the "My exports always sound like shit when I use FL." That's not FL; own up to the fact you need to properly learn your DAW. Too subtle? I hope not.
--And WolwerineBlues, (by the way, I have assume that your name comes from the Entombed album of the same name. If so, well played!!) labels will usually push this, but it is really a judgement call. They usually just want to touch it up so it is radio ready, but they really do nothing that you, as say, a bedroom producer, can't do--there's absolutely no reason that you can't entirely produce your own album, if you know the score. The biggest setback that bedroom producers have, when trying to find a well balanced mix, is to find a club/venue and a real studio or a comparable location to listen to it in; most people have access to a car, home stereo, monitor, headphones, etc.
I have room to grow as a producer, (I don't trust people who think that they have it all dialed,) but FL has never been an obstacle for me, as per mixing or mastering.