Premium Shipping extension broken by migration

This is a bit of a show-stopper for me.

I sell wargaming models and their weight is measured in grams, not kilograms. From JigoShop’s perspective my lowest premium shipping band was 0.001 kg. That wasn’t a problem in the 1.x branch.

Putting together an order manually after migration to 2.x was weird – no shipping options were present. Migration had turned off the Premium Shipping option (probably something to fix!).

Turning it back on didn’t add the missing options. Taking a look in the settings for the Premium Shipping extension I found that all my price bands were gone.

Okay, I looked up my rates and tried to re-enter them. I set them up and hit “update” aaaand:
Please enter a valid value. The two nearest valid values are 0 and 1.

So my weight options are 0 kg and 1 kg. I wish all my orders were over 1 kg (that’s a lot of miniatures!) but they’re not. I need to control things in at least 10g increments, not 1000g.

I’m going to need a fix for this ASAP as it’s a paid extension. The CSS issues I’m having I can fix mostly on my own but this one is on you guys.

(Also please, please, please, let me set my preferred unit of measurement as grams!)