Actually it is in the game, just not in the recollection room, you can find 2 in the slum if i remember correctly but i don't know for the 2 next.
I think that's because these 4 scene where added after the original release and then never added in the recollection room.
[Edit] I think the two i mentioned right above are ending, the first one is "END_Kyoukan" and the second one is "Engel_gangbang" who looks like a bad ending from the picture, there is also a 5th scene where the MC suck the dick of a man in a onsen or something like that, now idk if i missed a CG or if i mentioned them all but if you want to see by yourself if you the game on your computer you can click on the folder "www", "img" and finaly click on "picture" and you will see all the picture used for the CG in game (both SFW and NSFW).