shipping module: Need shipping price based on percentage of purchase AND flat price.

[RC_Cola]

My dropshipper has the following shipping criteria and I need to replicate this in ZenCart.

Under $25 total purchase: 6% of total purchase + $7.50
Under $75 total purchase: 5% of total purchase + $6.50
Over $75 total purchase: 5% of total purchase + $5.50

Thank you in advance for your assistance. I've tried on my own to find the solution but came up empty.

[Ajeh]

You will need to customize a Shipping Module for this, but can you tell us if this is always the same formula for everyone?

Or will you need different formulas for different Zones?