Some asian stringers omits a cross string near T-joint. This way, They could string a few more rackets with a 200m roll. And make a little more profit. They would insist that replusion power will increase without one string. But that's a hype.
If a stringer is skillful enough, one requires only one pack of string.
But, using 4 knots, I did sometimes snap cross while pulling then I have to open up another pack. Still, no mistake no two packages. Only one.