Shipping Calculation

I need a little help with some shipping calculations.

First issue...when I try to create a new shipping rule with a flat rate cost it doesnt save the value. Bascially I enter Total Number of Items == 1 with a Flat Rate calculation of $3. When I click OK and then go back and edit it the flat rate is back to $0.

Second issue...There doesnt seem to be an option to create a shipping rule for TotalItems in my Cart. My pricing structure works like so:

1 item = £3
2 items = £4.50
3+ items = £5

The only option I can find is for total unique items which wont do what I need. I tried adding a new calculation called TotalShipping which is = [Quantity]. I could then use the 'Number of items with specific column value' but I cant figure out how to use it.

I am using PayPal standard payments with no dedicated shipping provider.

Any help would be appreciated.