That 195mm would be right Pete, 35mm per frame and 10mm each side.
That allows Macow to work out the internal width of a 6 frame nuc should he want one.
Always check the box's various lengths with the appropriate frame:
internal length will be the frame bottom bar length plus 7mm to 9mm beespace at each end.
inside the shoulders will be the top bar length plus 1mm clearance at each end.
The shoulder width is 460mm minus (the (top bar length plus 2mm) / 2)
The internal shoulder height is the top bar height (9mm) plus the height of the runner 6mm = 15mm.
The Nuc depth is the whole depth of the frame plus the thickness of the bottom plate (inset) plus 15mm to 25mm (frame bottom to floor distance)
I believe that the bee space on the floor is less critical and the extra height ensures that a pile of bees are less likely to be damaged by putting the frames in on top of them.
Using plans, always check that the figures stack up correctly and that appropriate bee spaces are maintained.
Any comments re my understanding or otherwise regarding the frame bottom to floor distance please?
Construction techniques and exact materials will of course vary.
Checkout HedgerowPete's fine video He's got the technique and I know how it should be but make em naturally squinty