There are a number of things that can cause those discrepencies.

- Refunds. Depends on when the merchant processes the refund. However, once it hits their bank, the amount must be transferred and processed by your bank within five business days according to federal law.

- Charges. Think about it from the merchant's point of view. You don't want to sell something to someone that doesn't have the money. So, the charges go through immediately.

- Payments. Same rules as refunds.

- Batching. Some banks and merchants batch things and process them once per day. I've bought things late Friday night that don't show up until Tuesday.

- Transfers. Same as refunds.

- Bill Pay. Banks generally have electronic funds transfer authorizations with other businesses. Those generally take two days or three business days to process (day one for my bank, day two for the receiver). If not, then the bank has to physically print a check and mail it.

- Weekends. Most banks only process things Monday-Friday.

>When I charge something against my bank card, debit or credit, my available account balance almost immediately reflects that amount. When I have money tranferred into my bank account, PayPal or a refund on a purchase, I usually will not see anything regarding that transaction from 4 to 10 days. Why is that? It makes me feel that the entire commerce system is evil and only out to screw with my money.