So you want to make a non-realisitc setting realistic just for one item? If you look after it you will find tons of things in DH that are inconsistent and maybe do not even make sense. But they are used to simplify the game.
When you start to make the game realistic for the sake of one item. Where do you want to stop? Shall your players spent 3 hours of gametime to find an armorsmith on an imperator-forsaken world that repairs their armor because after four penetrating hits its protection value has degraded into nothing? Does the game actually benefit from such changes? I say no, it does not. You are offered Shields with different mechanics. Ignore what they are called, hell I do not even care. I use them for what they look appropriate. And if I want a Pavese-Like deployable Cover I Take a tower or naval shield. If I want a personal tactical shield I take the arbites one. It is quite easy. Everything in the Rulebooks is just a suggestion you can change. They even tell you to give things a name and to make a normal Stubber Pistol into a MK. 3 Lucius Pattern Personal Defens Automatic or what ever.