I don't believe you have to worry about those details because the accuracy of the predicted shell side pressure drop is not that good. I have never found anybody or a computer program - HTRI included - that could predict shell side pressure drops with enough accuracy such that the nozzle losses could make a difference.
Shell side losses are very, very difficult to predict and the only exception that I have ever experienced is the ability of captive technology used by specialist companies (such as Graham condensers) in predicting (& guaranteeing!) the very small pressure drops in their vacuum condensers. But these devices are very special and arcane in design. These special devices are very different from a conventional shell & tube design and their design is a well-kept secret. But even they have a conservative calculation and carry contingencies in the calculated design.
If you have a problem with nozzle losses in a S&T exchanger, I believe the best approach is to use a conservative design; i.e., use larger nozzles than calculated or eliminate impingement plates and use other techniques such as distribution shrouds - such as the old Braun heat exchangers used to use.
Art Montemayor concentrated his right comments on the STHE shell side pressure drop, the most difficult to calculate with a degree of accuracy.
Also on the tube side of HE, pressure losses include inlet and outlet nozzles, as for the inlet and outlet of tubes, both generally taken for liquids to be 1 and 0.5 velocity heads, for sudden contractions and sudden expansions, respectively, (Perry et al. Chemical Engineers' Handbook).
