Unfortunately no, sorry! My schedule is so full that I am no longer able to offer custom development. However, we do maintain a Developer Directory, here: https://slicedinvoices.com/developers/developer-directory/. All of the developers in our directory have expertise with Sliced Invoices. If you need custom development, the best option would be to contact one of them.
If you have any other questions just let me know.
Best wishes,
David Grant
Developer of Sliced Invoices