I'm running a Magento 18.104.22.168 build with the 'Tax Calculation Method Based On' setting set to Total but running into the issue of tax and total prices coming out at 1 pence less than it should be. I wondered if someone could help with figuring how to correct this. I have already changed all of the default rounding and precision in various files from 2 to 4.
As an example, Placing an order for 79 of a product with a Unit Price of £2.46 (Ex Tax) the Total (Ex Tax) price is correctly coming out at £194.34. However, the Tax line is coming out at £38.86 and Magento is rounding this from £38.868.
My client would prefer this rounded to £38.87 - since this is how the HMRC and Sage Accounts round these figures. The Order Total would then be £194.34 (Ex Tax) + £38.87 (Tax) = £233.21 (Inc Tax).
Because Magento is currently placing the tax at £38.86 (1p out), the Order Total is also 1p out at £233.20 instead of £233.21 from what Sage Accounts calculates.
This would place a Unit Price inclusive of tax of £2.952 instead of £2.95 (which is also how Sage Accounts would handle this).
We still need the site to display the price as £2.95 in this instance but the customer would need to be charged £233.21 instead of the £233.20 that Magento is currently displaying.