Free hand: uncountable

Free hand [countable; singular]

​ Unrestricted freedom or authority: They gave the director a free hand to cut the budget wherever she wanted​

https://www.wordreference.com/definition/free%20hand

However, the Random House Learner's Dictionary explains the NOUN GRAMMAR CODES as follows

[count] it can be counted and has a plural. It can be used with the word a or an before it.

[singular] only used in the singular with a singular verb. It can be used with a or an before it.

Therefore, isn't adding both codes in the same word contradictory?

Solution 1:

Free hand is "countable" and "singular". So is "potato". If there is more than one potato in the bag you have a bag of "potatoes".

If I gave a "free hand" to both Fred and Jack to pursue their respective duties, I could say I gave both Fred and Jack "free hands".

There is nothing remarkable about this.