I am not sure what names you refer to. In Delta app one can select the name of the loyalty program from a pop up list, and then type the corresponding member number.

So for El Al one can only choose from the selection "El Al Israel Airlines / Matmid club",
and at the "Member Number" field I tried to type my matmid.number, with or without the checksum last digit, none seems to work.

When I select any other airline, like Korean or Air France it saves the information even if I feed any random number, so it seems that the app does not really check anything, it only ignores El Al?