You make spreadsheets sound easy on Amigas. You'll be challenged to find any decent spreadsheet software for Amigas, let alone up-to-date accounting software.. AmiCygnix probably has the best spreadsheet support though.
GNumeric is a very nice spreadsheet especially since the revision where you can start it straight from Workbench without loading up AmiCygnix. I've got some very very large & complicated spreadsheets I use for work and GNumeric runs them great.