+Some parameters may take arguments of a specific type.
+Anywhere a numeric value is required, an arithmetic expression may be used,
+provided it is surrounded by parentheses. Supported operators are:
+.RS
+.RS
+.TP
+.B addition (+)
+.TP
+.B subtraction (-)
+.TP
+.B multiplication (*)
+.TP
+.B division (/)
+.TP
+.B modulus (%)
+.TP
+.B exponentiation (^)
+.RE
+.RE
+.P
+For time values in expressions, units are microseconds by default. This is
+different than for time values not in expressions (not enclosed in
+parentheses). The types used are: