Fist off, thank you for bringing us your question! I'm going to break this down into two parts. The first part will deal with identifying the PCV system and how it works. The second will discuss the smoke and its diagnosis.
From the sound of it, you understand what a Positive Crankcase Ventilation system is for and, in general, how it works. I don't have a Perdana to look at in person, but this picture looks about right from my research:
. Just in case, the PCV valve and visible system is circled(badly)
All PCV's have two things in common: they connect to the intake somewhere behind, as in closer to the engine, the throttle plate and they all connect to one of the valve covers or crank case. If you'd like to read a longer, more detailed explanation of how all this works on a boosted system, click here.
The shortest answer is this: When under boost, either the PCV is completely disabled or vented to the outside. The reason why is that forced aspiration can cause air to flow into the crankcase, creating its own host of problems. So either your system has a cut off, causing the PCV to close while the turbos are active or a bypass that leads to a vent. In the pictures of OEM engine on your vehicle that I've seen, it looks like it simply closes the PCV.
Now on the the smoke diagnosis! First off, I absolutely agree with starting at the PCV. You would be amazed at how many times I've had the honor of telling a customer that their engine is fine, they just need to replace this $15 part and the smoke will stop. If it is stuck open, I've seen an intake suck most of the oil out of a system in a very short period of time. And seeing the smoke increase at idle makes sense to me for this to be the issue. The smoke may be stopping when under load due to the bypass from the turbos.
It sounds like you already know this part, but I want to include it for completeness of my answer and in case someone else needs it. The easiest way to check to see if the PCV is your problem is to disconnect the hose from your PCV at one end or the other and stick your finger in it. If there is oil on your finger, it is time to replace your PCV. If not, then I would plug the end leading to the intake and run the car for a few minutes. Is it smoking now? If not, then your PCV is still the issue. If the smoke continues, you may need to run it for a few minutes to clear the oil out of the system.
Just a warning, if this has been happening for a long time, there could be oil built up in your intake.
Let us know if this solves your problem. Please feel free to follow up with any questions that you may have. If the issue turns out not to be PCV related, please close this post and open a new one.
[Edit]
Okay, so I would really appreciate input from a more senior mechanic than myself. My theory is this: your system has two PCV/CCV systems. The reason why I believe this is that you have those two ports right night to each other. If one was a vent, it should be on the other end and it would lead to the intake before the throttle plate. Instead, one leads straight down and the other to the intake manifold somewhere. It's hard to tell because there's some sort of control valve around the intake and the hose. You can kinda see the hose loop over and then under again into the intake. Kinda. The other just disappears beneath the engine. You might look into finding the service information for it. I don't know where you are, but here you can go into an Autozone and ask them to look it up for you.
