AH module - some questions

[Energia 20]

Hello,

Today I decided to use wrobot for auction's for the first time. I have read some topics about it but still got some questions like:

1) How to use this button under list of items ? 'Appraise selected items at 80% (by default) of minimum price' - what does it mean ?

2) Minimum, maximum, average and center - this variables can be chosen for scanning AH. What are these for ?

3) Should I use this button manually from time to time to build some database similar to auctioneer addon or it is happening automatically ?

4) When the bot finds any bargain and collect it from mailbox we can use the bot to list that same item on the AH. It is possible to list items always 1 copper cheaper than the rest of current competition on the market? Instead of list with always the same price ? 

Cheers!