In my opinion, you need to consider the formula that was applied in the past. When did we start to consider gifts of $500? I am not an expert in this field, but if this formula and this amount have been applied for a long time—and I believe that that's the case, although I'm not sure—it would be better not to change the amount at this time.
If that amount was set 25 years ago, $500 is worth much less now. Over the years, I do not believe that we had any problems involving MPs who received gifts of that scope. Since we almost never had problems, why should you have to declare every small gift now? We're talking about small gifts, but I don't know what the value should be. Regardless of what it is, I wonder why it should be less than $500 when $500 was acceptable 25 years ago.