squid-deb-proxy refresh

[J]

Can someone explain the refresh lines in the squid-deb-proxy config?

for example:
# refresh pattern for debs and udebs
refresh_pattern deb$   129600 100% 129600
refresh_pattern udeb$   129600 100% 129600

I know that the first and third number are Minimum and Maximum
times... but how to they work?

in the example, does that guarantee that debs will NOT be refreshed
any sooner than 36 hours after they were last refreshed (if called by
a host using the proxy)?

And I saw a definition of the percentage, but I really don't get how
the percentage works.

If I have this:

0  100%  100

does that mean the file will be refreshed any time after it is 100 seconds old?

If I have this:

0 50% 100

does that mean the file will be refreshed after 50 seconds?

I've been searching and reading for a while now and haven't found
anything that makes those lines actually make sense or explain just
what the minimum is for, nor the percentage.

Thanks
jeff