Using NSNumberFormatter to get time value in decimal and round up
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I need to be able to calculate the time difference between two dates and then store that value in one digit precision decimal format.  So if the time difference is 6 minutes then I need .1 to be returned, if it is 3 minutes I still need .1 returned, but if it is 7 minutes or 12 minutes, I need .2 to be returned.  The subtraction of the time difference is working correctly:

    NSTimeInterval interval = [currentFlight.landtime timeIntervalSinceDate:currentFlight.takeofftime];

That returns as expected so if the difference is 6 (minutes), the value I get back is 0.100000.

I also need to display this value to the user in a `UILabel`.  When I use this number formatter, 0.100000 gets displayed as .2 instead of .1:

    NSNumberFormatter *ftDecimalFormatter = [[NSNumberFormatter alloc] init];
    [ftDecimalFormatter setNumberStyle:NSNumberFormatterDecimalStyle];
    [ftDecimalFormatter setMaximumFractionDigits:1];
    [ftDecimalFormatter setMinimumFractionDigits:1];
    [ftDecimalFormatter setRoundingMode:NSNumberFormatterRoundUp];

I have tried all the difference rounding methods, but none seem to work.  Any suggestions?