This is bad advice and totally misses the point of rebalancing in the fist place.
Statements like “you can be moving money from well performing assts to poorperforming assets” suggests that you should attempt to time the market.
Rebalancing is not a timing mechanism. It suggests that you stick to a strict aset allocation. Best bet ona small portfolio is that you rebalance once a year, larger portfolios might go every 6 months. I would make sure that if you have some losses that you may wnat to consider booking those losses for tax purposes. Please remember if bought back within 31 days there is a wash sale rule that negates this.
Rebalan cing and dollar cost averaging are 2 strategies. There are advisors our ther who will argue against this. William O’Neil would suggest that concentrated positions in winning sectors backed with stop losses of 7% to be a more effective strategy.
To me there is not a right or wrong strategy. It is like east coast offence or west coast offense. The trick is to find one that works and stick to it.
I would suggest reviewing your portfolio every 6 months and rebalancing once a year. Take some money off the table for your winners adn realize that the losers are getting cheaper. Find comparable ETF and Mutual funds so you can book your losers for tax loss and simutaneously keep you portfolio dicsipline.