The Petrov Affair

After completing the Adventure Lab (The Petrov Affair), you will be in possession of some suspicious numbers: 

AL1 - ABCD

AL3 - EFGH

AL4 - JKLM

AL5 - P

Make sense of them and find the final drop location by using the suspicious numbers as follows:

JGL(G-L)PKC / E(M-L)HDK(A+L)(B-D)F

NOTE: the log must be signed to claim this cache...