NECA labour units incorporate much more than installation time. They include your handling time, supervision, planning, layout.
You have to be careful when bidding by NECA units.
NECA has labor units for almost everything. Not only main material such as pipe and wire, but also screws, inserts, bushings, you name it. You could labour everything you will be installing, but then your labour would be very high.
NECA also has different levels of difficulty of installation, column 1 to 6 ( at least in my old copy). Column 1 is the one most estimators use.
One of the best Change Order techniques, is get the engineers to agree to use NECA 1 labour units for pricing. Guaranteed profit$$$
