That's not how the gap between sell-through and shipments works. If we estimate 1.5m Switch consoles on shelves now, then that's a pretty similar amount to how many Switch consoles were on shelves when entering the current fiscal year, therefore there is nothing to add onto the sell-through numbers for the current fiscal year. ~17.5m in sell-through also means ~17.5m in shipments.
I'm not sure I understand this logic. But maybe I'm missing something.
Switch that were on shelves on the 1st of april 2019 should have been counted as shipped during the Q4 FY2018 isn't it?
On the other hand, switch that are on shelves right now were shipped during FY2019 so they should count for this FY.