Folks, just because a history book says it happened doesn't mean it happened.
There are plenty of textbooks out there that claim Columbus ran into opposition from people who believed the Earth was flat. That's a flat-out lie.
Similarly with these books on the second world war. If somebody claims something occurred, it has to be DOCUMENTED. If someone says "the JU88 had MG131S" fine -- show us the evidence: show us the procurement inforamtion, field installation notes, captured aircraft information, a photograph, something. Then we can talk about changing it.
But to go out on the basis of some secondary source written by someone who doesn't tell you where he got that silly idea from is frankly bad history. Go check out the pretty pictures at
www.luftwafferesourcegroup.org, and read their loadout descriptions. Did it all happen that way?