Allow 3 decimal precision when entering weights and prices
When entering weight or prices, the values are truncated to 3 decimal places. This causes issues when you want to enter weight in Kg and also problems with shipping costs being rounded to strange amount when Tax is charged on shipping.
For example, we want to charge £12.95 for shipping some items. We charge Tax on shipping. If when configuring Table Rates we set Tax Status to Taxable, we need to enter the Row Costs as £10.79 or £10.80.
In checkout, the shipping cost is shown as £12.94 or £12.95 because of rounding. So how can we enter the EXACT price we want to charge for shipping, £12.95, but ensure the Tax breakdown includes the £2.15 Tax @ 20% for Shipping?
The obvious solution would be to alow people to enter costs with 3 dicimal precision. Another solution would be to have a "prices are entered inc TAX" checkbox and then store the EX VAT price in the existing rate_cost column with the necessary decimal precision and the inc Tax price in a new "rate_cost_inc_tax column.
I have checked that directly editing the prices in the database to 3 or more decimal points shows the correct prices on the frontend.