Payment Processing Fees Calculation seems off?

Hello, not sure if this has been brought up before, but the math being used to calculate the processing fee seems to be incorrect. This results in a slightly below target net after the processing is done by the card processor. The example is based on a $92 total transaction with a 2.9% processing fee and a $0.30 transaction fee:

Events booking cited 94.97 as the total cost to the registrant. This was calculated as (92 * 1.029) + .3 = 94.968. Results in a processing fee of $2.97
Processer assessed fee as $3.05 This was calculated as (94.97 * 0.029) + 0.3 = $3.05
This results in 94.97 - 3.05 = 91.92 which is 0.08 less than target. Aggregated this will add up in net difference.

I'm not a math guru, but to properly calculate processing fee of 2.9% + 0.30 transaction fee on $92 I believe the math should be calculated different in event booking:

((92 + 0.30)/(1 - 0.029)) - 92 = 3.0566 - Essentially $3.06 fee so 95.06 total charge

Processor would then calculate (95.06 * 0.029) + 0.3 = $3.06 

This would then result in a net of $92 as expected. For clarity I am using the Square payment plugin, but I would assume the calculations would be independent of the plugin and likely be a product of the main Event Booking app?

Thank you.

Hello

The fee has been calculating like that for years. Right or wrong, to be honest, I'm unsure but I could not make changes right now because it is widely used and could cause unexpected behavior if I make the change

If you want the fee calculate as you described, please:

1. Create folder components/com_eventbooking/helper/override on your site
2. Get this file, unzip it, upload the received file to components/com_eventbooking/helper/override folder

Then it should work as you want. This change is implemented using override, so it won't be lost when you update to future releases of the extension.

Regards,

Tuan

Hello Tuan, thank you for the updated helper, this would have taken me several days to figure out and I appreciate your prompt response. There is one error in the helper in that the original amount was not deducted from the calculated fee, which resulted in the fee being the original amount + fees. I've made the update to the helper and have attached it here as an updated version. This results in the correct value and fee. 

Thank you,
Tim

Great. Thanks Timothy!