I am working on a software project that is intended to replace the data entry done in Excel spreadsheets. We have a grid control that displays the data but it is edited in a form with tabs for different sections (over 60 columns in the spreadsheet). The users are complaining that it takes them longer with the tabbed form to enter the data that simply typing in a spreadsheet and moving to the next cell. So now I am wondering if there was an error in our UI design. Are there any good books or other resources which describe the most efficient UI for data entry? 
Best design for data entry UI
ui