I am with a boat having a polar file from ORC VPP expressed at 6, 8, 10, 12, 14, 16, 20, 24kts TWS. We have found Expedition reporting a polar BSP with instrument measured TWS >30kts. In our post-race analysis we are trying to answer why the yacht was not achieving that BSP. How does the software calculate this PolBSP if the source polar tables do not have a value close to the observed TWS/TWA? We seek to understand if our sail selections (or other boat factors) explain being 2-3kts below what Expedition says is the PolBSP, or is the software exaggerating the PolBSP because there isn't a TWS/TWA close to the conditions observed?