Chris - I would do as you mention and add one more node at the point of
max sag. The bolt-down option prevents flood losses through the
manholes; it will also cause higher pressure locally and in the
surrounding part of the system. So run it first without the "bolt-down"
option and see if you are getting flooding. If not, the HGL is good and
the "bolt down" option is inoperative. Note that these program "bolts"
only stop water. They do not stop air. If the real bolts and gaskets
stop air leakage, you might get higher internal semi-transient pressures
than the program indicates.

Ron Kilmartin
ronkilmartin@attbi.com