Thanks for testing.
The PaEC logic understands (or should understand) the incremental updates that might be downloaded. I don't know why your subsequent PaEC presses should take so long.
In my tests of US Chesapeake Bay
(Region 4) ENCs, I find that immediate second press of PaEC, after initial processing takes only about 10 seconds. There is nothing to do. The progress bar just zips along.
Then, if I immediately update some cells from NOAA, only a few of the cells are updated, as you would expect. Time for this depends on how many updates have been downloaded. Usually pretty fast.
You can test this logic.
In a typical ENC folder, you will find the base chart ENC file as .000 extension. Updates have extensions of .001, .002, and so on.
1. Temporarily rename or move the last one or two update files.
2. Run PaEC
3. Restore the renamed update files.
4. Run PaEC again. Check the log, and you should see one new SENC built, incorporating the latest update. It should run PaEC very fast.
All this activity should be reflected in the logfile.
It is surely the intent that updates be processed logically by PaEC. Lets work this out.