Pressure Drop adustment in Section 14 Tables

The software should be auto-sizing the baseline system airflow so no need to try and "design" it by increasing the cfm. You can double check your baseline fan power calculations using the spreadsheet found in the Documentation Toolkit tab above. The baseline pressure drop adjustments are intended to compensate for the effect on the baseline fan power related to issues like MERV 13 filter and ducted returns. So you don't do any further adjustments.

Probably not. In general you need to completely fill in the Section 1.4 tables. I am not sure which version of the Section 1.4 tables you are using or even specifically what you are suggesting that you could leave blank. The allowable fan power is automatically adjusted by the pressure drop adjustments.

OK. In Table 1.4.7A it is important to know that you should enter each separate system in its own column or the fan power calculations will not be 100% accurate. You would enter the cfm of supply air from the energy model. You then enter the cfm associated with any of the applicable pressure drop adjustments in the bottom of the form. For example, do not enter the supply cfm for ducted returns unless 100% of the supply air is returned. Use the same proportions as the corresponding proposed system (if the return is 90% of the supply in the proposed apply this proportion to the Baseline). The spreadsheet will then accurately calculate the allowable baseline fan power for each system. Make sure to read the instructions and notes at the top of the page to make sure it is working right.

Model the proposed as designed. It is certainly possible that the proposed fans could use more energy than the baseline fans.