Sandpiper 360PDEK A/C
I went through my complete a/c system and retaped every joint including the ceiling air registers. Also plugged up the end of run duct in ceiling. Using an anemometer before and after, I gained .8mph at the terminal air registers. It's 100°F here and the air coming out of register is 66°F.
Previously I pulled off tops of units and resealed the openings where wiring went thru an the installer leftist sized holes allowing air to go into attic area.
A little work, big rewards.