There are 2 small issues on my Osc site (version [url removed, login to view]). Its about the weight-based shipping cost, based on 3 categories (13 kg).
1) if weight 10-13 kg: theres inconsistency in price between product detail page and checkout page.
2) if weight >13 kg:
Theres VAT difference in shipping price between detail page and checkout page.
3) If weight <10 KGS theres no problem.
A quick fix is required, hopefully today.
If you do this cheap, quick and fast I may have more jobs for you.