Explain reportEvent to custom destination urls (with macro substitution)

Fenced_Frames_Ads_Reporting.md

@@ -47,7 +47,7 @@ The following new APIs will be added for achieving this.
 
 ## reportEvent (preregistered destination URL)
 
-There are two sets of parameters that can be used to invoke the `reportEvent` API. In the first, fenced frames can invoke the `reportEvent` API to tell the browser to send a beacon with event data to a URL registered by the worklet in `registerAdBeacon` (see below). Depending on the declared `destination`, the beacon is sent to either the buyer's or the seller's registered URL. Examples of such events are mouse hovers, clicks (which may or may not lead to navigation e.g. video player control element clicks), etc.
+There are two variants of the `reportEvent` API that are invoked with different sets of parameters. In the first variant, fenced frames can invoke the `reportEvent` API to tell the browser to send a beacon with event data to a URL registered by the worklet in `registerAdBeacon` (see below). Depending on the declared `destination`, the beacon is sent to either the buyer's or the seller's registered URL. Examples of such events are mouse hovers, clicks (which may or may not lead to navigation e.g. video player control element clicks), etc.
 
 This API is available from all documents in a fenced frame that are same-origin to the mapped URL of the fenced frame config (i.e., the ad creative URL that won the Protected Audience auction).
 
@@ -107,7 +107,7 @@ window.fence.reportEvent({
 
 ## reportEvent (custom destination URL with substitution of preregistered macros)
 
-In the second set of `reportEvent` parameters, fenced frames can invoke the `reportEvent` API to tell the browser to send a beacon to a specified destination URL, where macros in the URL are substituted to values registered by the buyer's worklet in `registerAdMacro` (see below). This specified URL must be a valid HTTPS URL.
+In the second `reportEvent` variant, fenced frames can invoke the `reportEvent` API to tell the browser to send a beacon to a specified destination URL, where macros in the URL are substituted to values registered by the buyer's worklet in `registerAdMacro` (see below). This specified URL must be a valid HTTPS URL.
 
 This API is available in the same contexts as `reportEvent` to a preregistered destination, i.e., documents that are same-origin to the fenced frame config's mapped URL. However, there are additional restrictions on the origin of the destination URL. The interest group declaration includes an allowlist of origins that may receive reports using this mode of `reportEvent` (custom destination URL with macro substitution). If at any point a report is attempted to a disallowed origin, access to this mode of `reportEvent` will be shut off for any ad loaded from this fenced frame config, for privacy reasons (to prevent reidentification by using the allowlist to encode cross-site data about a user in binary with its choices of allowed/disallowed origins). Note that this only applies to this mode of `reportEvent`: `reportEvent` to a preregistered destination will still work.