One of the ways to increase the power output of a solar cell is to have a right balance between the number and size of conductive transmission lines on the top side (sun facing side) of the solar cell. Having the right number of transmission lines is quite easy but having consistency in the dimensions of the transmission lines is quite challenging. Even though the transmission lines serve the purpose of carrying the current, oversized and inconsistent transmission lines cause shadowing of the solar cell reducing the effective output.
Ability to screen print a metallization paste with <100 microns line width is half of the problem. The other half is using a low slump metallization paste. Here are two cross sectional images of the cured metallization past which forms a transmission line. Both paste are equivalent in terms of conductivity and contact resistance but one has higher slump factor than other. The shadowing caused by the high slump metallization paste can be easily observed (almost 30% more shadowing than the low slump paste).
In conclusion the cells made with low slump metallization paste will always have higher peak watt output and aggregate power output as compared to the equivalent ones made with high slump paste.