I am currently meeting an issue with the LOOKUP function in excel

sometimes it would find the right data and sometimes not.

I made a picture example bellow, the two examples at the top gives the wrong results while the two at the bottom gives the right results.

Is my syntax or use of LOOKUP incorrect? How should I correct it to have the expected result?

here is the csv table of the data (my German computer uses ';' separators also in formula you may have to edit it )

```
;"LOOKUP(C2;D2:D4;A2:A4)";;;;;
D4;"=LOOKUP(C2;D2:D4;A2:A4)";3400;3400;;;
CI;;;2390;;;
F5;;;900;;;
;"LOOKUP(C6;D6:D11;A6:A11)";;;;;
D4;"=LOOKUP(C6;D6:D11;A6:A11)";3600;900;;;
F4;;;3600;;;
CI;;;2390;;;
D4;;;900;;;
B4;;;2250;;;
D4;;;900;;;
;;;;;;
;;;;;;
;"LOOKUP(C15;D15:D17;A15:A17)";;;;;
D4;"=LOOKUP(C15;D15:D17;A15:A17)";3600;900;;;
F4;;;3600;;;
CI;;;2390;;;
;;;;;;
;"LOOKUP(C20;D20:D27;A20:A27)";;;;;
D4;"=LOOKUP(C20;D20:D27;A20:A27)";3600;900;;;
F4;;;3600;;;
F6;;;3650;;;
F5;;;3700;;;
CI;;;2390;;;
D4;;;900;;;
B4;;;2250;;;
D4;;;900;;;
```