Here is the using tips of xhorse vvdi key tool max on generating 40 bit 4d ford transponder key.
Use super chip and generate the chip by selecting the option for the chip (New 4D chip (40 bits)).
Ford 80 bit chips are backwards compatible with the 40 bit keys. Just stock the 80 bit and you good to go.
Don’t delete keys as you can only use 1 super chip and need 2 keys minimum to program in or car won’t start.
Just add key, don’t do akl (all keys lost), you can add 1 key without another key by selecting add key instead of AKL.