Hello, everyone.
This one was rather tougher to understand at first, but I think I get it now. When we’re calculating the range of IPs that a single MC MAC address corresponds to, we basically tweak the 5 blue bits
Since a multicast MAC is 23-bits long, it won’t be big enough to account for the 5 bits in the 28-bit IP address. This means that one MAC will correspond to 32 different IPs. Since you have 5 bits to tweak, and if the remaining 23-bits are stable, the MAC address effectively remains the same because it doesn’t provide enough bits.
Also writing it down in ranges is rather complex and should be avoided. If I’ve said that the following IPs map to the same MAC:
224.0.0.5 - 239.128.0.5
You could assume that even 239.127.0.5 would map to the same MAC as I’ve specified it as a range 
I suppose it always makes more sense to either write it all down or remember the fact that only 32 IPs map to one multicast MAC which means 16 IPs if the second octet is 0 and another 16 IPs if the second octet is 1, or just write it like this:
224-239.0.0.5
224-239.128.0.5
Thanks!
David