PayPal only adds shipping when I use whole numbers in Carrier Fees PS v.1.0.0.5

[DaveGoodman]

Hi - I'm pretty new to PS - I've been asked by a client to make some changes to his PS 1.0.0.5 set up, which I've done, but this one's proving a problem:

When I put use an amount with a decimal point and pence (e.g. "1.50") in the Carrier Fees weight ranges, the shipping price isn't included when going to PayPal. The shipping shows up correctly in the cart and checkout right up until the user gets taken to the PayPal page, where it's dropped from the total.

If I change the amount to a whole number - say "2" - it works fine.

I've checked through all the settings in PayPal - and made sure that the override option is selected in Shipping Conditions.

I've double-checked the site prefs against an almost duplicate PS website the client has which doesn't have this problem.

I've thought upgrading the system to 1.2.4 might help, but want to be sure it's not just something simple I've missed.

All (sensible) suggestions welcome!

Thanks!