Having a 6% random chance in all 100 drawings is the same as having 8.3% in the around 72 of those 100 drawings that will have no matching digits. By boxing 5 different digits in every drawing, it's a given you can't win all the next 100 drawings so the only necessary percentage is how many of the around 72 drawings you need to win to show a profit and that number is 13.
There are many methods for choosing which 5 digits and while unlikely, it's possible to match 3 of the 5 every time 3 different digits are drawn. By using a progressive betting method it's possible to show a nice profit by winning less than 13 times out of 100 drawings too.
"Surely you could find better ways of profitting from that!"
Most pick-3 boxes pay $83 or $80 for a $1 bet so playing 10 different boxes reduces the win expectation to about 8 to 1 on each bet whether the wager is $1 or $60 on each box. To show a profit you need to win once out of every 7 times if you make the same bet each time. If Shawn can continue to win 3 out of every 9 drawings it will be a very nice profit.
There might be better ways of getting a larger profit by using another method but that's a different topic.