Stupid question about sports betting lines

[Shades]

I don't bet on sports, but do often look at the betting lines.

I understand the basics of the "+" and "-" values that are assigned to the favorite and underdog.

But can someone explain what the difference is in the following nomenclature is for the following random example:

Oklahoma at Tennessee (-7)
Oklahoma (+7) at Tennessee

Both of these scenarios favor Tennessee by 7.
Why not just always assign a "-" number to the favorite?
Why even bother with assigning a "+" number to the underdog?

Or does it have to do with how someone places a bet?:
Is the first case for someone who places a bet that Tennessee will win by at least 7 points?
And the second case for someone who places a bet that Oklahoma will lose by less than 7 points?

Thanks in advance.

 

[sonofUT62]

There’s sometimes a difference in the payout based on who you take. For example you might get +110 to take the favorite or +115 to take the points. Those are just examples but the amounts aren’t always the same even though it’s not a ML bet.

 

[Vol$_Deep_11_9]

There’s sometimes a difference in the payout based on who you take. For example you might get +110 to take the favorite or +115 to take the points. Those are just examples but the amounts aren’t always the same even though it’s not a ML bet.

Best explanation, or one of them, that you’re gonna get on this

 

[Boca Vol]

There’s sometimes a difference in the payout based on who you take. For example you might get +110 to take the favorite or +115 to take the points. Those are just examples but the amounts aren’t always the same even though it’s not a ML bet.

Typically it would be -110 & -115 not a +. You typically have to go to the alternate lines to get + odds.