You could also use this array formula...
{=SUM(MID(TEXT(E6,"0000"),{1,3},2)/{24,1440})}
Note: This is an array formula which must be entered using the Control+Shift+Enter key combination. The outermost braces, { }, are not entered by you -- they're supplied by Excel in recognition of a properly entered array formula. For more on array formulas see the Excel Help topic for "About array formulas and how to enter them".