EAc4 Equipment Life not represented accurately in ref. guide

Regarding EAc4 equipment life, the reference guide tries to summarize the equipment life by system from the ASHRAE Applications Handbook 2007, but does not accurately represent heat pumps. Here's my point: Ref. guide states: "Assume equipment life as follows (from ASHRAE Applications Handbook 2007): -Window air-conditioning units and heat pumps, 10 years -Unitary, split, and packaged air-conditioning units and heat pumps, 15 years" If you look at the equipment life table from ASHRAE Applications Handbook 2007, the first bullet is partially correct as window AC units are listed as 10 years (although the table has no window heat pump). The issue I have, is with the second bullet, as it basically says that all other heat pumps have 15 year equipment life. The ASHRAE table lists 15 year life for Residential single or split package AC, Commercial through-the-wall AC, Residential air-to-air, and Commercial air-to-air. However, it lists >24 years for Water-cooled package AC and Commercial water-to-air heat pumps. For a water source AC or heat pump unit, 9 year difference in service life makes a big difference with the refrigerant calculation. Has anyone run into any problem with this by using 24 years for water source heat pumps?