Hi Shirokuma,
Yes this can be something that throws players off and makes them lose focus often.
Its difficult because everyone is individual and finds their own way to manage to keep score as well as concentration on the game. I think the best way is just trying to practice keeping score in training and practice matches as much as you can. When in matches say the score out loud which will re-in-force it in your head as well.
There aren’t really any clever techniques to this other than practice I think, but remembering who’s serve it is and how many serves they have had can help because then you will at least know the margin of points and weather it is an odd or even score in terms if numbers.
Keep up the practice!
