Files scanned

One of those dumb questions about something eludes me...

I run a full system scan with Ad-Aware: 87,000 files scanned

I run a scan with Stinger: 18,000 files scanned

I run a full scan with Counterspy: 102,000 files scanned

I run Panda's online ActiveScan: 164,000 files scanned

Why the huge disparities?

File types, directories, etc that are scanned.

...also some scanners only count an archive (.zip, .cab, etc) as one file scanned, whereas some count the files inside an archive as individual files.

... and also the depth of the archive...