[Grammar] ‘amount to’ VS ‘run into’

[northpath]

Is there any difference in the usage of phrasal verbs ‘amount to’ and ‘run into’ in these contexts?
His monthly earnings amount to about $3,500.
The cost of repairing the damage could run into millions.

 

[Lynxear]

Both sentences are fine.

The only difference I see is that "amount(s) to" would more often used when a definite total is involved, whereas "run into" in this context would be more often used when the final total could only be estimated.

I cannot imagine "run into" used in the first sentence. I have no real reason other than it does not sound right to my ears.

With the use of the conditional verb "could" in the last sentence, I think that either phrase is possible, especially in common speech.