Maybe whoever wrote the software for the PDA didn't understand the Pronto Hex format well enough.

Most Pronto Hex has 0000 as the third value. That software may not work right with any Pronto Hex for which the third value isn't 0000.

Perfect NEC1 has 0022 0002 as the third and fourth values. If you change those to 0000 0024 it becomes the same signal in NEC12, which isn't really correct, but is understood by your LG and apparently can be sent by your PDA software.

If you change the Form line in NEC1 to

Form=;16,-8,D:8,S:8,F:8,~F:8,1,-78,16,-4,1,-174

That should produce NEC12 (same as manually changing all the 0022 0002 to 0000 0024).