Inconsistent use of heating capacity retention for 2-speed and var-speed HPs

[shorowit]

When the user specifies a heating capacity retention in their HPXML file, we use it for both speeds in the 2-speed model but only use it for max speed in the variable-speed model (and continue to use the default for min speed). Seems like we should use it for both speeds in both models, or only max speed in both models?

[shorowit]

@jonwinkler's initial reaction is to just modify the maximum speed curve.