How to read the asset quantity list of open asset protocol?
According to the Open Assets Protocol Spec, the amounts are encoded in something called the unsigned LEB128 encoding. So for 300 the binary looks like:

100101100

You have to pad to a multiple of 7 (we have 9 bits, so this becomes 14):

00000100101100

Now split into groups of 7:

0000010 0101100

Add in a 0 bit for the very first one, and 1 for every other group of 7:

00000010 10101100

In hex, this is:

0x02 0xac

Put this in Little Endian order:

0xac 0x02

You can do the same for the 624,485 number and get the 0xe5 0x8e 0x26.