Interesting question. Try putting together a CASE statement using the ROUND() function. Something like this:

declare @num numeric(10, 8) = 83.00381433 ;

SELECT CASE

WHEN round(@num, 5) - @Num < 0 THEN round(@num, 5) + .00001

ELSE round(@num, 5) END;

I'm not sure if this is the best way to do it, but it should work

Edit: corrected boneheaded arithmetic error.