I wouldn't say they have it wrong, but I definitely think that Jakarta Post have missed the point (Surpise! Surprise!).
When you appeal a verdict, you take a serious risk, risk than Ahok, rightfully advised, didn't want to take: your sentence may be decreased, remained the same or... be increased.
In the case of a Peninjauan Kembali (judicial review), you have no such risk. At worse your sentence remain the same, at best you get some or all charges dropped and a reduction of your sentence.
Also, if you wish to appeal a decision of court, you have 7 days to do it after receiving the sentence. If Ahok would have do it, not only he would have taken the risk to have his sentence increased but he would have had all the clowns of the FPI creating an uproar till the High Court decision be published.
A PK (judicial review), unlike an appeal, can be done pretty much anytime as long as the sentence is binding, and can be done several time. Ahok lawyers intended to let the dust coming down, and the clowns to be focus on anything else, before moving. This is what they have done.
This being said, I don't think that Ahok expects much about it... iunless of course if it has been dealt since the beginning, like the detention in Mako Brimob.