precision and accuracy of a measurement system
Generally if an accuracy is given as 1.5%, it is assumed that this means ±1.5% unless otherwise stated.  Thus you should not substitute one for the other.
Precision can be better than accuracy. In your example, however, since the readings are near the edge of the circle and spread around, the precision is not much better than the accuracy.  If the readings were closer together then the precision would be better than the accuracy.
Precision could be expressed using ± meaning that the readings will cluster around the average reading within that percentage.
Again, if you express precision without the ± sign, then the ± will generally be assumed. It is better to use the ± sign and avoid any ambiguity.