Well, I tried this Simplified Pricing here in France, it's horrible. First of all, it increases gross earnings by 15%+VAT, in my case: this additional 15% guest fee+VAT= 18% in plus of TOTAL Gross Earnings!!! And we pay taxes on gross eranings, which amounts to paying more taxes with Simplified Pricing. In addition, for those who are not subject to VAT because to small a business, this risks increasing your taxable turnover and falling into the obligation to pay VAT in addition to higher taxes!
Not to mention it DIDN'T bring me more bookings.
Fortunately we can easily deactivate it here:
The ServiceFee structure
https://www.airbnb.com/account-settings/payments/service-fee