Data Validation: using date in as initial date in range

I am looking to use data validation to make sure that dates entered into the spreadsheet fall into a specific range based on an initial date.
Specifically, I want the date entered into column L to be within 3 days of the date entered into column A*. PTSDCP Participant Tracking.xlsx
I have tried using an absolute reference on column A ($A2) so that L2 refers to the date in A2, and L3 refers to the date in A3 ect, but so far the data validation only works for L2 and not any rows below it.
How can I resolve this issue and only use one data validation command (so that it continues referencing each date in the column without creating an individual command for each date)?

Thanks,

dmorl


**I also want the date entered into column O to be within 7 days of the date entered into column A, and the date entered into column Q to be within 14 days of the date entered in column A**

7/5/15 is the current date in A3. If the validation was working correctly and I typed 07/20/15 into L3, I should be stopped from entering that date because it falls beyond the 3 day range. However that is not the case-- can just enter that date without a problem. Try it yourself: put in a date into A4 (that is past 07/01/15), and then put in a date into L4 that is more than 3 days past the date in A4. The validation should prevent you from entering it and prompt you to enter another date, but it doesn't.

...oh duh, I had it from $A2. When I changed it to $A1 as the start date and $A1+3 as the end date it fixed the problem.
Thanks for bearing with me!