Notice that with a word having more than three वर्ण, the last वर्ण is उत्तम and the second-last वर्ण is उपोत्तम.
In the meaning of गोत्र (non-ऋष्यपत्र), अण् इञ् suffixed प्रतिपादिक and with उपोत्तम गुरु-applied in the fem. gender has ष्यङ्. For example, बालाकि ष्यङ् - बालाक्या (बालाकि has इञ् and the उपोत्तम आकार is गुरु through दीर्घञ्च - hence the ष्यङ्).