Anyway from the OPC website from a Q&A you can take it how you wish:
"As to the implied questionwhy do ministers have their membership in presbytery instead of in the local church?in some Reformed traditions, particularly those of Dutch heritage, ministers are in fact members of the local church. In our own denomination the membership of ministers is in the presbytery, though such ministers have communing fellowship with the local church.
There are three reasons or arguments in favor of this practice: First, we expect our ministers to have a broader range of responsibilities over the whole work of the church than do the elders. Their responsibility, more than that of the elder, is in the region. (Yes, individual elders from the different congregations are also called to serve the regional church through their presence and voting at meetings of the presbytery, but not all elders are called to do such.) Second, we recognize the need for a large measure of specialized education for our ministers that we do not require for our elders (e.g., knowledge of Greek and Hebrew). Consequently, we think it more proper that they are subject to the examination and oversight of others with that same level of training. Finally, since the ministers are members of presbytery, that fact makes any discipline of them, or any dispute over their call to a particular church, immediately the concern of the presbytery. This provides a large window for the regional church to view the happenings, and to participate in working to promote the purity and peace of the church."