Can we create a field for Variance?

Hi Experts,

My client wants to see the following in SAP Business one 2007A PL:08

1 - A variance column that will calculate the difference between the A/P Invoice Price and the PO price. This could be a dolar amount or a %. How do I do this? Can I define an UDF for this?

2 - A flag at AP invoice stage where it will alert saying that the A/P invoice price is different than PO price. How do I create alerts?

3 - Lock certain fields in the header information of Item Master Data, Business Partner Master Data etc. How do Lock a specific field. Users are changing too much of information randomly.

Thanks