Incorrect Tax Rate on Inclusive Prices

I've created a GST tax of 7% and set it at admin/store/settings/taxes. When a product is processed I notice that tax is charged at a lower rate (approx 6.5%). See screenshot attached [File: incorrect_tax_rate.jpg].

All product prices are inclusive of tax. How does one fix this?

Also in the invoice two tax amounts are shown [File: double_tax_rate.jpg]. Why doesn't the subtotal excluding GST already deduct the first GST amount?