This is a good strategy, but if you are always following this strategy from the scratch, i am sure that you are going to have more losses than earnings, since there are more than 200 coins listed on the major exchanges.
So no, this is false, and it doesn't works.
My strategy on my short term trades is too sell it once it goes on top 30 gainers. These are the coins that are based on hype and will not end well in the long run so it's my own signal for selling it all.