Hello, MaaAdjoa, and welcome to the Grammar Exchange!
The hyphen is correctly used. What you should avoid is the repetition of "saving," and this you can do by dropping the first occurrence of that word and leaving the first hyphen orphan (i.e. waiting for the word that will complete its sense later), or eliminating it altogether:
1- time- and cost-saving manner
2- time and cost-saving manner
Alternatively, you can find:
3- time and cost saving manner
Of all the options above, I prefer (1). Perhaps David, our moderador, can tell us what he thinks or knows about this issue.