The Pricing Offset customization sets a "Fixed" or "Percent" price change on the Recommended Price (after all other customizations have been applied).
This was mainly developed for users who want comparable prices for mapped listings from different channels, and can be used in scenarios where they want to increase the price for a certain channel to cover the extra fees/cost. 
Offsets can be applied even if the listings are not mapped, in case the user wants the final price to a be higher/lower than the recommended price by certain percentage/amount for all the dates.
For example (mapped listing): A user has listings mapped in PriceLabs from Airbnb and VRBO, and wants the Airbnb prices to always be 8% higher than the VRBO prices. This can be done by going to the Airbnb account level settings on the Customizations Page, clicking on edit, and selecting the "Percent" option on the Price Offset customization. Here, the user can enter the desired offset value in the space provided (don't forget to turn the toggle switch on for pricing offset!).
As long as all the other account, group, and listing level customizations are the same between the Airbnb and VRBO listings, and the parent and child pairs have the same base price, price parity will be maintained but every rate sent directly to Airbnb will be exactly 8% higher than the rates sent to VRBO.

For example (un-mapped listing): In case you wish to apply the offset on an un-mapped listing, go to review prices of that particular listing > customizations > advanced customizations, and then follow the same steps as above.
As mentioned before, this setting is applied on top of all your price customizations, which includes Fixed Price Overrides, Orphan Discounts, etc. This means that the Recommend Price of a listing that uses this customization may go above your Maximum Price or below your Minimum Price.

It is advisable to check twice before using Pricing Offset in case the user uses a PMS, that is linked to various channels and websites. Because the final price after offset will be pushed to the PMS, which in turn will be pushed to all the other channels, and that might not be the requirement!