Massive =IF together with =DATE formula

Hello.
I am trying to create a formula which will have date as an output depending on variable.
Variable are following:

4
5
L6
U6

The idea is to add a certain amount of years and month to the TODAY date, depending on the variable.
The output date (month and day) are pre-defined = 1 of May
Though the year varies. It will be 4 years for 4, 3 years for 5, 2 years for L6 and 1 year for U6.
The trick is that most students will be registered in september, but some might register after new year and this is where I am not sure of how to make year add up correct.
I tried to make up this formula which gives output of 42491 =\


=IF(B5=3; DATE(YEAR(C11)+4;MONTH($D$2);DAY($D$2)); IF(B5=4;DATE(YEAR(C11)+4;MONTH($D$2);DAY($D$2)); IF(B5=5;DATE(YEAR(C11)+3;MONTH($D$2);DAY($D$2)); IF(B5=L6;DATE(YEAR(C11)+2;MONTH($D$2);DAY($D$2)); IF(B5=U6;DATE(YEAR(C11)+5;MONTH($D$2);DAY($D$2));0)))))