While 175-180 is good, you may be "fooling" around with balls before you are ready to. It's hard to say. SOme people, learning, should stay with one ball, say a medium solid resin, and then learn thru ball speed, revs, rotation adjustments, learn to play both medium-light oil and medium-heavy oil patterns.
BUUUTTT, it's very hard to say that via typing you are ready for this; that is why a coach, seeing you bowl and execute is so important.
You may be averaging 175 because you're not making as many spares as you can OR you may not be throwing as many strikes as you can.
On the other side of the coin, many modern bowlers never change their release; they just move back and forth between balls. What is best for you or possibly which mix of both balls and releases may work best for you, both mentally and emotionally, is very hard to say, via typing. Don't mean to be redundant, but that's the truth.
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"We get old too fast, and too late, smart."