Yeah, this is the common misconception if you're not familiar with the principles of versioning, so you immediately apply your understanding of mathematics to make assumptions about numbers you see. You might, for example, see v0.9.3.2 which is mathematically meaningless. But in versioning (done correctly), that has a very clear meaning. Like
dolfe67 said, versioning works differently. The periods
are delimiters, but they are not the same as decimal points and serve a different purpose.
And like
Dark Silence pointed out,
sometimes the pattern you expected will happen. It's not all that common, however, primarily because it's almost impossible to know for a fact you're exactly 50% of the way through a story (or 90% or whatever). It's even not always clear for a developer whether they're
close to a specific percentage.
The entire point of numeric versioning is to understand two simple principles. First, a lower number will always be followed by a higher one (so just as 6 follows 5, 10 follows 9), which is how you know you're running a later version of the program (game, etc.). Second, the periods are delimiters, separating types of change from one another. In the X.X.X.X pattern, the 4th number is a tiny change, like a typo correction or a similarly small change. The 3rd number would be more like a patch, for fixing a major bug in a game, for example. The 2nd number would be a new version, generally coming with new content and/or a major overhaul (such as a redone combat system or adding a phone to a VN that wasn't there before). Finally, the 1st number typically represents a full version of the game / program, such as a full first release, ready in the way a game in a plastic case sold at a store would be.
If you understand this basic idea, it will help you better know how things are progressing. And one final note: versioning will ofc differ here and there, from developer to developer. Some only use chapter numbers, some will use the date of a release, etc. So rather than assuming a version should be a certain way, if it's different than you expect, I'd try to understand how a specific developer is using it instead.