Whether coding standards really matter for maintainability generally depends on how much information you expect to be carried by the formatting.
We generally assume that indentation follows block structure, so indentation standards tend to be very important. I've wasted hours over bugs that were hidden by incorrect indentation.
Naming conventions may matter if the coding standard dictates a different styles for different scopes (e.g. LeadingCapital for global names, etc), or if type info is embedded in the name (pszFoo, lBar, etc).
Beyond that, coding standards help readability but that's about it. That may or may not be an issue depending on the team involved; one benefit of a uniform look is that you get less of "You're stuck fixing that code forever because I can't read it".
Whitespace standards (outside of indentation) are generally of marginal to no use IMHO. I'd follow reasonable whitespace standards, just for that uniform look, but nobody should be spending hours on it. The fancier the coding standard, particularly as it applies to variable naming, the less useful it is in general.
You shouldn't be losing "hundreds of hours" in code reviews, though. Either you're deliberately being obtuse about things or your coding standards are insanely complex, or uselessly ambiguous. There are a number of things I don't like about the coding standard I work in now, but I stick to it anyway because it makes the code more uniform and easier to read. Have you tried doing the same?