Can be several things. There can be a variety of triggering events and quantity survey options to ensure that surveys allow for flexible quantities during surveys, this is done when the drawings are either incomplete, there are no drawings for the land, known changes are coming, or if the land contains items for mining or harvest and the quantities are the numbers of commodities. The surveyor lists the quantities (lots, parcels, sections, number of commodities) from analysis, then "escalates" the quantities based on assumptions for change and additions. This can be boundary changes, boundary line moves, corner point moves, or an escalation of number of commodities based on the quantity surveyed - you name it. Basically, since escalate is to intensify, in quantity surveying it means to get into more detail based on what you know will be happening, based on analysis, and not just what is on the drawing or what you just finished surveying. Also, if your quantities are being given to estimators as the next step in the project, escalation then will mean a factor applied to the present cost of the item surveyed (a parcel of land, or a number of the commodities) so that a future currency amount expended can be represented in it's higher currency total as currency today is worth less in the future.

Yes, I know of no hard and fast definition for the term "escalation" within the surveying profession, so it could mean one of several things depending upon the intent of the author. You should ask the author for the meaning of his/her words.