Not an answer to your question, but I figured that I'd try and run it
on my server... here is my results.

I'm using: mysql Ver 12.22 Distrib 4.0.24, for pc-linux-gnu (x86_64)

I ran all of these queries in this exact sequence:

If I run 'select * from client;' I get 264 rows
If I run 'select found_rows();' I get the correct value of 264
If I run 'select * from client limit 100,10;' I will get 10 rows
If I run 'select found_rows();' I erroneously get 110

So I guess its pretty much broken... I'll stay away from it!

Jeach!