[Typo3-shop] Tax calculation incorrect?

[Robert Markula]

JoH wrote:
>>In our soon-to-be online shop the price without tax
>>(PRICE_TOTAL_NO_TAX) is not calculated correctly.
>>We use these settings for the price calculation:
>>   TAXpercentage = 16.00
>>   TAXincluded = 1
>>
>>Example:
>>When the total price (PRICE_TOTAL_TAX) is 10.00 euro, then the price
>>without tax (PRICE_TOTAL_NO_TAX) is calculated as '8.62', but the
>>correct amount would be '8.40' euro. The difference is 0.22 euro.
>>
>>With a product that costs 1000 euro (PRICE_TOTAL_TAX), the
>>PRICE_TOTAL_NO_TAX is calculated as 862.07 euro, but it should be 840
>>euro. The difference of 22.07 euro is a bit more significant.
>>
>>Is anyone else experiencing this? Where does this difference come
>>from?
> 
> 
> You should try to correct your understanding of percentage calculation ;-)
> 
> 840 + 16% = 840 * 1.16 = 974,40 != 1000
> 862.07 + 16% = 862.07 * 1.16 = 1000,00(12)
> 
> If the price X is including 16% Tax the "No Tax" price is
> 
> X/1.16
> 
> So the example calculation is correct.

Looks like I saddled the horse from the wrong end. Of course you are 
right. Thanks for your example!

Regards,
Ro