BUG - Decimal Price on Custom Field Variant Type

[mtaras]

Hi,
I have setup custom filed of cart variant type with extra cost additional on price.
But I have a problem with decimal add prices.
At admin the extra cost saved as decimal correctly.
But in frontend the select list seems to round the extra cost.
I think that the problem is at the creation of select list options.

See product http://petshop88.gr/%CF%83%CE%BA%CF%8D%CE%BB%CE%BF%CE%B9/%CE%BB%CE%B9%CF%87%CE%BF%CF%85%CE%B4%CE%B9%CE%AD%CF%82-%CE%BA%CF%8C%CE%BA%CE%BA%CE%B1%CE%BB%CE%B1/dental/loofah-bone-detail where the extra cost rounted to 0 or 1. But when I select a size, the add of price is correct at the final price. So I think that the problem is at the display of select list.

Some help please?