We're working in a 1.9 & php7; detected this issue with paypal suspect fraud (due the difference amount).
All correct in frontend (apply taxes); but in checkout and calculation, magento uses the grand total without taxes.
Actual wrong order calculation:
Product price without taxes + shipping with taxes = total amount to payment
Switch to php5 and calculation is correct.
Some idea?
Thanks!
Best Answer
Solution
I've created a magento module to solve magento issues with totals calculation for php7. The issues I've experienced in particular were that taxes have been added twice to the grand total for pay with amazon module on the amazonpayments checkout page.
Credits
The answer provided by archigrafix in this post (https://magento.stackexchange.com/a/97107/35665) solved my issues - so this is simply the fix packed into a module.
Module:
https://github.com/hartmut-ltd/magento-php7-totals-fix