Combined taxes issue on invoice

[acaravaca]

Hi!

I'm having a problem on prestashop invoices using a combination of two taxes on a client group. I'm using an extra module for advanced invoices numbers, but they told me that this issue is on the breakdown calculation method in prestashop.

I've two taxes: 21% + 5,2% and breakdown taxes activated. Well, in the tax details tab on invoice, i've the name and amount of each one of them OK, in two lines, the total tax amount is well calculated too for each line,  but in the row on the middle the base price it's divided by two, getting half of the base price on each line, but i repeat the total amounts are ok... 

Any help with this?

See attachement,

Thanks