It makes sense in that Germany was on the decline and the metals they used to make late-war tanks were much lower quality than the metals used to make their early and mid-war tanks.
Actually, it's not entirely true.
The German steel quality was about the same through the entire war, with no evidence that supports the late war decline in quality.
It is a fact though, that their steel and welding quality had a much greater variance than those of any other major nation in WW2, so while most likely majority of their tanks had at least good armour, there were also a lot of "bad apples" with bad quality armour.
My personal comment would also be that I'd suspect the "bad apples" German tanks were better documented in Allied/Soviet tests, since it's more interesting to write about something unexpected (like armour cracking under HE shells) than something expected (thick armour holding off a lot of shells).
Psquieh was streaming at the time and he said that they are same as the regular P4s but their turret and frontal armor aren't as good.
The frontal armor is 160 compared to 180 of the Ausf G.
Some other minor differences - their main gun shoots very slightly slower (very, very slightly), it's slightly slower (6 vs 6.3) but it's MGs are stronger (about 15% to 40%, depending on range).