Rule sets and custom promotion not working together

[Jeanne298]

So, according to Airbnb, "A rule-set always applies first. Any additional discount you add, such as a custom promotion, is calculated using your rule-set price."

However, I have a rule set right now for a length of stay discount for a certain holiday time period (5 day length of stay = 20% off).

I also have a custom promotion for this same month of 20% off.

I thought then that for guests just wanting a short 3 night stay, they would get the custom promotion of 20% off. 
I thought then that for guests wanting a longer stay, say 5 nights, 6 nights, etc., they would get both for a combined 40% off (that's what I want to happen).

However, that is not happening. No matter what, the only discount is 20% off.

Basically I want the added benefits of using a custom promotion during the time period, but I want to offer a better discount for a longer stay. Like, if someone wants a full week at Christmas, I am happy to offer the larger discount. But I don't want to set the custom promotion to 40% because then guests could book just 2 nights for that large discount and that is NOT what I want to offer.

What am I doing wrong?

[Emiel1]

@Jeanne298 

Are you using Smart Pricing ?

(then the ruleset will not work)

If not using Smart Pricing:

IMO the ruleset will overrule the custom promotion, so discount is always 20%

Discount on discount is always tricky and results can be unpredictable.

Maybe set your promotion price as prices in the calender for that month, then apply a ruleset for the time period you want to offer discount for 5+ nights stays

Or create a ruleset for the month,applying the discount for 1 to 4 nights stay.

Then create sa econd (almost same) ruleset for the special time period, but add the high discount for 5+ nights stays to it.