I have updated the fiddle to use parseFloat. Seems like the numbers are incrementing now.
var A = parseFloat(id);
The reason why it was working with values above 20 was that it was just reading the part before decimals each time it tried to increase. So 20 became 21 and 22.05 and so on. As long the the value before decimal kept changing, it showed different (but incorrect) answers.
On the other hand, 10 became 10.5 which when parsed yielded 10. As you can see, this cycle continued endlessly.