The 40% figure definitely needs more context. What was the average increase in sales the prior 6 months? And did it decrease back to normal after the experiment

The 40% figure definitely needs more context. What was the average increase in sales the prior 6 months? And did it decrease back to normal after the experiment was over? And a single month of sales increase might be due to timing in sales cycles. Maybe the prior month there was a lot more overtime than usual, and there were a lot more leads this month, and prospects further in the sales cycle. I am all for a 4 day work week but this experiment is lacking a bit.