Having been in both the CRC (as a youngster) and the PCA (more recently), I found the approaches officially similar. Minister candidates are closely examined by presbytery/classis. Elder and deacon candidates are approved for election by the local session/consistory. How much the local body instructs those candidates beforehand and then examines them depends on the church and is up to its elders. So in terms of stated procedure, I was of the impression that Dutch and Presbyterians are pretty much the same.
Yet when I became a PCA deacon, I had instruction and was quized on both theology and my lifestyle. I wouldn't call it an "examination." It wasn't nearly as thorough as what a minister candidate would go through. But it was more thorough than I'd seen in the CRC.
So why does the process appear to you (and to me) to be handled somewhat differently? If it isn't codified, why is there traditionally some difference. I have a theory.
When I was young, the CRC had a stipulation that every elder/deacon election had to have at least twice the number of candidates as there were open positions. So at most, only half the guys approved by the consistory ever got elected by the congregation. In such a situation, a church's elders may not want to put the entire slate of men through rigorous training and examination—knowing that at least half of them will end up being turned down. The URC church order doesn't seem to have retained this stipulation, but traditions have force. URC churches may simply not be used to doing much officer training.
That's my theory. Perhaps more knowledgable folks can comment more fully on the Dutch and Presbyterian officer election traditions and tell us if it holds water.