Income doesn't get allocated based on days in state.  Each item of income is sourced to a particular state where it was earned.  The PY dates at the bottom of the Fed Info Wks are your starting point but once you enter the state names and all of the federal income then you come back to the Fed Info Wks and Quickzoom into the PY Allocation Wks to tell the software which state the income is sourced.  W-2s pull automatically from the state portion of the W-2 Wks but most of the other items are most easily split on the PY Allocation Wks.  Then there are sometimes adjustments made in the individual state modules.

Rick