Would you ever combine soft armor and ICW hard armor from different manufactuers?

#1
I was listening to a recent P&S podcast and the consensus was that mixing soft and hard armor brands when going ICW if a bad idea.

My question is, is this necessarily so even with good brands? Due to my height (6'4") I'd need a SAPI Large sized hard armor plate or something less covering that might acutally allow for greater mobility. At present I'm thinking of the Large sized Mayflower LPAC vest with the matching Velocity VS-63A1 Soft Armor package.

Then I want from amongst the lightest Large SAPI or similarly sized Swimmer Cut ceramic plates that can withstand M193 and M855. Velocity doesn't make a special threat protective plate (so III+ type lightweight armor plate) that's larger than 10" x 12. So would something from an outfit called Chase Tactical, their RSTP Rifle Special Threat Plate III+ ICW, be acceptable or does mixed armor get you killed in the streets, as the hipster shooters say?
 
#2
VS does cover both of those plus 855A1 with the BZ and it’s available in S-XL so I believe 14” tall is the largest. As for mixing I believe that is the episode where Chuck talks about the shoot through of the Ranger armor package where essentially the only difference between the new vest they were testing and the USMC design package was the cut of the soft armor. Stopped in one, shoot through in the other. All materials the same just a different cookie cutter in the soft armor of one. So yeah smallest of things matters.

I’ve done a fair amount of professional research on armor for work as part of my procurement assignment and I still get consulted now. You must be skeptical of everyone. There are so few people I trusted within industry just because it was the nature of good procurement. I liked to see the raw data from the testing agency. I remember I had one major vendor who used ICW armor systems. They had great looking products, the right pedigree, and sported major international contracts. They are a good company. One of the vests they submitted passed the lab testing. It stopped the rounds but they went through the plate and stopped in the soft armor. The energy delivered to the soft armor was so intense that while it didn’t penetrate, it actually burst the “skin” of the shell material used to waterproof the armor package. So there was no pass through hole but there was a hole on the body side where the shell of the armor was blown out. The backface was less than the maximum so it passed. What do they call the guy in med school with the lowest passing grades? They call him Doctor too.

In this scenario there was not a lot between pass and fail and I know that shot would have hurt like a bitch. Juxtapose that with a package where the round stops in the plate and never touches the soft armor. With ICW you are potentially using an armor package where the bullet is designed to penetrate the plate and rely on the soft armor to catch it. Mixing and matching is a horrible idea. Potentially fatal. It’s alit more science than people give credit. That’s why for my guys I always insisted on standalone components. Because I knew there was always a chance they would mix and match stuff down the road. I just eliminated the possibility of that failure point.
 
#3
VS does cover both of those plus 855A1 with the BZ and it’s available in S-XL so I believe 14” tall is the largest.

Mixing and matching is a horrible idea. Potentially fatal. It’s alit more science than people give credit. That’s why for my guys I always insisted on standalone components. Because I knew there was always a chance they would mix and match stuff down the road. I just eliminated the possibility of that failure point.
Thank you for that excellent and thorough explanation of the factors at play and how to interpret passing tests! Alright, so it seems like I really need to get a hold of some VS BZ plates in the right size then! Too bad that all too many places that sell their products refuse to sell to civies.

As an alternative, beside the weight penalty, is there anything wrong with running stand-alone plates inside a soft vest capable of holding the SA plates?