Good. Don't worry about these warnings though, MSI put them there mostly for liability and "support avoidance" reasons. Ideally, they want to sell you a product and then never have to deal with it (or you) again. The more you tinker with it, the higher the chance you're gonna contact the support about it. Unfortunately, each BIOS has a myriad of bugs (typical "bananaware" that ripens after it's sold), which slowly have to get fixed via BIOS updates. Buyers who realize that certain things happen because of an immature BIOS will update their BIOS, and they generally are happy when things run smoother afterwards. People that "don't know what they're doing" might update the BIOS, the custom settings get reset to defaults, and they're lost, so they are more likely to contact support.
MSI also like to obfuscate things as much as possible by (in your case) delivering NO changelog whatsoever, or for the retail boards, posting just one- to three-line-changelogs, although each BIOS update can contain literally dozens of little fixes and improvements. They're not alone in doing this, but it certainly doesn't inspire confidence when you don't know what you're updating the BIOS for.
I have explained it all a bit more
here.
Anyway, you made the right choice by getting 2x16 GB DIMMs.
You still calling them "SIMMs" could mean you are in the PC game for 20+ years? In that case, you should slightly know what you're doing by now
