I had a 4-night midweek stay in October at the IC Paris Le Grand booked as 2 x 2-4-1s. It caused an element of surprise at checkout when they wanted to charge full rate for 4 nights but of course my printouts came to the rescue.

I was especially surprised as the stay was in the final week of the Rugby World Cup when many hotels had doubled their rates and most were fully booked.

I have had other 3-night stays including midweek at IHG hotels booked as 2-4-1 for 2 nights and a separate reservation for the 3rd night. All in Europe btw.

So it's usually worth checking just in case.