As someone below pointed out, the fact that they give the hair count increases in percentages with no indication of base hair counts means they are giving us much less information that it may have at first seemed.
However, perhaps this line of thinking could help us at least divine a “minimum” hair count increase for one of the members. Let me know if you find any flaws:
Hair counts within a certain area can only be whole numbers. 15 hairs, 30 hairs, etc.
The final hair count, after the measured increase, can also only be a whole number.
If one of the trial members had an increase of 103%, in other words, he doubled his hair count in that area plus three percent, then three percent of his initial hair count must also be very close to a whole number (we also have to take rounding of that 103% into account).
Around 30 hairs (possibly 29) is the first number where an increase of 3% gets you something approaching a hair. For example, an increase from 29 to 59 is an increase of 1.034 percent. From 30 to 61 is 1.033, etc.
So at minimum then, the person whose hair counts increased by 103% must have had around 30 hairs to begin with. Of course, this tells us nothing of the quality of the hair grown.