Decimal places in Zone Shipping

Hi,

We have inherited a shop with around 800 items, all listed in kilograms. These items are all relatively small (around 50g in size), as such the items are listed as 0.050kg.

Shipping costs are worked out via weight. For example, to the US, this is what the shipping rates are listed as in admin (Modules>Shipping>Zone Rates>Zone 2 Shipping Table)

0.300:7.22,0.350:7.82,0.400:8.22,0.450:8.82,0.500:9.22,0.550:9.82,
0.600:10.22,0.650:10.82,0.700:11.22,0.750:11.82,0.800:12.22,0.850:12.82,
0.900:13.22,0.950:13.82,1:14.22

When I go to order, a "The shipping rate cannot be determined at this time" error appears, and the price is listed as zero. I believe it's because the shipping table doesn't like the decimal point.

In any rate, is there a simple fix to allow me to check the weights for less than 1KG, and work out the shipping for it?

Any suggestions?