How to list charge for extra guest without Airbnb screwing up the math?

Over a year ago I reduced the basic price by $10 and made an extra guest charge for a second guest as I
felt it fair to charge less for just a single guest. However, the website listing increased the base price by $10, and for 2 guests charged another $10 on top. Previously our price for 2 guests was showing at $57 with no extra charge for more than one guest. The change resulted in the base price going to $67 plus another $10 for a total of $77, i.e., a $20 increase over what we had been charging for 2 guests, and a $10 increase for single guest bookings. I contacted Airbnb and although my email was acknowledged I never received a satisfactory explanation. I therefore changed the base price back to what it used to be to include 2 guests.
I was hoping this glitch had been resolved so tried changing it again, but still get the same result!

Is there any way around this problem so my listing can show $x for single guest and $x plus $10 for 2 guests?

Sorry to hear you have this problem. I also reduced the base price of my double room to favor single travellers, and added 10€ after first guest, but it has been working perfectly for me. Anyway, I only had a solo traveller once, most are couples. Airbnb should solve this, I recomend you to insist.

So the new price you put in is: $47 base price and $10 for every extra guest above 1?

I think it may take a little while for new price to show up, like a day, at least that has been my experience.

That is correct. It seems that I can put in any base price I want and it will show up correctly on the opening page/photo PROVIDING that I do not check the charge for extra guest under edit pricing, as once I do that it increases both the base price by the amount for extra guest even for a single guest. In the booking section if extra guest is checked it puts up the final amount yet again. If the base price was set at $47 and the extra guest was at $10, this results in the base price showing as 57 and if their are 2 guests then the final price shows as 67, and if only a single guest then final price shows as 57 when it should only be 47