It 'ought not' ('to') make any difference. [=(more commonly) it shouldn't make any difference]
Children 'ought not' [='should not'] run near the pool.
If my math is correct, the result 'ought to' be zero.
(..) I'm thinking of taking the morning off sick. You cover the fort for me? That's swell. Thanks. Yeah, no, I'm sure I'll feel better. Okay. Okay. You're sure you ought to do this? I'm not sure what I'm sure of. Burt, you got some company. Can I offer you a cold drink? Oh, yes, ma'am. A cold drink (..)1999 The Green Mile
(..) Del's been asking for a box. Thinks the mouse will sleep in it, I guess. Might keep it for a pet. What do you think? You know what? We ought to find a cigar box... ...and get some cotton batting from the dispensary to line it with. Yeah. Yeah. That should do real nice. Man said get a cigar box. (..)1999 The Green Mile