Ah, ok - I see the weights.
.72 is slow for a 737 in cruise - the pitch seems appropriate. Not sure what cost index you used. Note that the optimum altitude indicated is purely a function of weight, not of speed (which means you probably fly too high for the slow speed calculated by the FMS).
The "green dot" denotes the optimum L/D speed with engines running, the top of the yellow bar will include a MACH buffet margin, so at high altitudes it will be "higher" than the green dot.
And - as Morten pointed out - if you have a "far forward" center of gravity, the tail has to push down hard to keep the plane level. This extra "push down" needs to be balanced by the wings, so they need more "nose up" to create the necessary lift. The saying is "As a rule - aft trim saves fuel"
Cheers, Jan