The 'tier' classification is highly subjective. For example, you classified Golden Lotus as tier 2, but it's a very established chain and has been around for a long time. They are fairly well organised and the experience is usually solid, although most MLs have a limited 'menu'.
Perhaps scrap it altogether, or maybe replace it with an estimation for how long the shop has been around under the same management: under 1 year, 2-3 years, 4-5, more than 5, or similar.