You can maintain one for more overdraft limits for a bank account. The overdraft limits are time dependent, therefore the total overdraft limit of the bank account may vary with time if you maintain multiple overdraft limits for different periods of time.
Example
The bank grants your company an overdraft limit of 100000 EUR for year 2013. Your company requests an additional overdraft limit of 50000 EUR for the end of the first quarter.
You define the overdraft limits in the system as below:
EUR, 100000, Valid from January 1, 2013 to December 31, 2013
EUR, 50000, Valid from March 25, 2013 to March 31, 2013
The total overdraft limit of Euro for this bank account in year 2013 is:
From January 1, 2013 to March 24, 2013: 100000 EUR
From March 25, 2013 to March 31, 2013: 150000 EUR
From April 1, 2013 to December 31, 2013: 100000 EUR