One trafficlight index is depending on 2 cells

Hey Everyone,

i really hope i can find some help here

So im creating this Orderingsystem for a friend of mine, where i implemented a KPI Index which changes it colour depending on how many days, since the order has been placed, passed by.
So far so good.

I used this formular: =IF(J4="";"";TODAY()-J4)

KPI.png

So my question is:
When i enter another date in "Ware bestellt" or L4, i want the KPI to turn green or maybe any other color to show that this product has been ordered.
Is it possible to that the KPI can get the data from two different cells? Maybe through a interlaced IF-Formula?

Thank you so much in advance !!!
Mona

Maybe:-

=IF(J4="","",IF(L4="",TODAY()-J4,1))