MAMEWorld Forums - The Loony Bin - Google search results question(s)

Using mame as an example, but seen that behavior using other keywords as well.

I realize that the results may vary as google tailors results per user.

Looking at "Mame" as keyword:

https://www.google.bg/search?q=mame&cad=h
About 31,800,000 results (0.31 seconds)

OK so far so good, then when you click on next a couple of times you see increments of ten in the URL:
https://www.google.bg/search?q=mame&start=30
https://www.google.bg/search?q=mame&start=40
https://www.google.bg/search?q=mame&start=50

And so on and so on...good.

When you reach page 25:
https://www.google.bg/search?q=mame&start=250

It shows up to 30 pages, click on page 30 it takes you to:
https://www.google.bg/search?q=mame&start=290

Good?
No, it is listed as page 27.
Which is itself actually a different set of results as to page 27 when you navigate to it from page 25:
https://www.google.bg/search?q=mame&start=256

Note that the page number results got weird there and are no longer in ten increments.

What gives?
What happened to all the millions of results?
If you choose the option to show the omitted results that are too similar, you max out at 71/72 pages and there page 72 is behaving weirdly too and still far from millions of hits.

Forcing a use of google.com limits the max navigable results to 22/23 pages before it gets weird as well.

Who is "Monika Mame", why is that last result on google.bg results and not for .com/.de/.nl/?
Will 2016 bring answers?

Happy new year.