Cipher or unknown language - historical perspective

[Stefan Wirtz_2]

*with a modern pen (You are not allowed to view links. Register or Login to view.)

Cursive[..]The clerks who produced these documents used a much thinner pen than what was used for formal book script. The flexible tip allowed for a faster pace and it gave the script a kind of “casual” feel.

While book script required the pen to be lifted between each stroke that formed the letter, with cursive script the pen remained on the surface of the page, with each letter connected by a ligature (or loop). 

From the same source. At beginning of 15Ct this technique was long and far established, writing better and faster than "1 movement down and offset" was easily possible. VMS has no linked letters, but clearly a lighter way of writing than the classic book typing.

 Nowhere there is definite evidence that they were drawn as one stroke.

And there is literally nowhere the definite evidence that all or most letters needed 2 strokes.
In that example picture, there are many characters shown where no second "landing" after an offset is visible.