12 Hour with quarter hour intervals not working for drop down box.

I've made a time sheet that calculates time based on the quarter how, but wanted to make things a little easier by having a drop down menu for the time interval entered. The data valuation list source setting is;

7:00 AM, 7:15 AM, 7:30 AM, 7:45 AM, 8:00 AM, 8:15 AM, 8:30 AM, 8:45, 9:00 AM, 9:15 AM, 9:30 AM, 9:45 AM, 10:00 AM, 10:15 AM, 10:30 AM, 10:45 AM,11:00 AM, 11:15 AM, 11:30 AM, 11:45 AM, 12:00 PM, 12:15 PM, 12:30 PM, 12:45 PM, 1:00 PM, 1:15 PM, 1:30 PM, 1:45 PM, 2:00 PM, 2:15 PM, 2:30 PM, 2:45 PM, 3:00 PM, 3:15 PM, 3:30 PM, 3:45 PM, 4:00 PM, 4:15 PM, 4:30 PM, 4:45 PM, 5:00 PM, 5:15 PM, 5:30 PM, 5:45 PM, 6:00 PM, 6:15 PM, 6:30 PM, 6:45 PM, 7:00 PM,

but it doesn't allow me to enter anything after 2pm because it seems to not allow anymore entries.

Does anyone know a work around for this? Can I list the values in another place and still show up in the drop down menu?

Please help.

I added another tab and entered the dates into individual cells and accomplished what I was trying to. Thanks for the help!