Is nested IF statements the best function to use

I am trying to decide which function is better to use in Excel worksheet where I am asking Excel to give me one of three responses. My initial function looks like this: =IF(ISBLANK(G6:M6)"Error",IF(G6=0),O6=F6/E6),IF(G6)=F6/E6,O6=0)))

I am working from my data (Frequency, Minutes per task, Days per week, and Total minutes per week). So users may enter 1 for frequency, 30 for minutes, 5 for days of the week, and Excel provides me a total of minutes.

From there I have cells marked Sun-Sat which allows users to leave blank, enter a zero, or enter a number of minutes for each corresponding day. Let's say cells G6-M6. I also have cells O6 through U6 that need to perform a function based on what the user does in G6-M6.

If G6-M6 is left blank I need Excel to return "Error". If cells G6-M6 contain a number of minutes I need Cells O6-U6 to remain blank. If cells G6-M6 remain blank I need cells O6-U6 to reflect minutes per week divided by days per week.

Hopefully that's not confusing