The name of town or city is actually the name of the post office which is responsible for managing the incoming mail, not the municipal name (even though by writing the municipality, the address can still be understood, provided that the correct postcode is given).
This is simply because the incoming mails are handled by the Kampung Kepayang post office which has moved to Simpang Pulai.
However, there are also some people who write "Simpang Pulai", "Ipoh" (which is the nearest city and also the municipality) or even "Kinta" (the district or daerah in Malay").
This is because they have their own post office to handle their incoming mails, which also covers Kuala Kuang, Kanthan, and Klebang.
One more example is the addresses of certain places e.g. Pandan Indah, Bukit Lanjan, Taman Melawati, etc.