Different chargeable ratios for trucking

Enabling an option to customize the chargeable ratio for trucking.

Some countries have different chargeable ratios (e.g. 1 cbm = 300 kgs, 1 cbm = 350 kgs) instead of the air freight (1 cbm = 167 kgs) or sea freight (1 cbm = 1000 kgs) conversions