kovarex: I transformed the problem to status based and tried to do a little analysis.
The original book shows this as an inferior solution, and I have to agree, as this seems to be ko-2, as white takes first, and when black retakes, white can go into the corner as an extra threat and take first again.
The normal solution is KO+ (attacker takes first)
P19-Q19-Q18 is also ko.