More details, are perhaps in order. The book explains this set of engagements in pages 252-254.
It seems that the Syrians had been attempting to divert water in the Golan Heights area.
The aim of the Israelis was to stop this, but rolling over the border with tanks to duff-up some earth moving equipment, or using lots of artillery to do the same, was not considered in order, as there was a brokered ceasefire in place at the time.
The whole exercise depended on the Syrians first breaking the ceasefire, thus enabling the Israelis to respond. Various engagements at various ranges (1500metres and up) using a variety of equipment took place, culminating in the APDS shot, which was apparently observed directly (although by off-board observers, which shouldn't be a surprise at that range).
The shot had been previously simulated in a training area that had been remodelled for the purpose.
According to the book, it was a first-round hit on a track, which caused the Syrians to move their earth-moving efforts to a distance of 22km, behind a ridge.
After that, the Israelis had to bomb the worksite and the occupation of the Golan Heights in 1967 ended the Syrian's waterworks projects altogether.
Can any of "our" Israelis confirm/contradict/expand upon this story?