New to Sheriff sales...could use some pointers!

[Pat Riley]

Hi All,
My name's Pat. I've been working in real estate for a little bit now and I'm starting to look to get into investment properties.
I went to my first sheriff sale in Berks county PA the other day. I had a list with all the properts up for auction and it gave the Minimum Bid amount and the Down Payment amount. Now it's my understanding that the down payment is 10%. What is this a percentage of? Estimated fair market value?
When the properties were announced the representing attornies would give the minimum bid then announce there Upset Price. And just about all of the properties went right back to the bank.
Now please tell me if I have the wrong assumption here. For the sake of round numbers, if the listed down payment is $20,000 (10% of fair market value?) and the Upset amount announced is only $75,000...this is a good deal, right? Obviously condition, locattion,ect come into play. But I just really want to make sure I'm wrapping my head around this the right way.

Any advice or tips are GREATLY appreciated!!!!