If you modify DCA strategy, it is not DCA anymore.
It is still DCA. It is similar to your practice with any technical indicator for your trading, you can customize many parameters in a same indicator and still can not change that indicator to a new one.
It might be better or worse than DCAing but it aint no DCAing. DCA means buying daily weekly or monthly with the same amount. Of course most people cant do it properly and it is because sometimes they buy $1000 worth of btc and sometimes a bit more or less. However thats still considered DCA ing as long as they keep buying.
DCA is still flexible and your example is true. Sometimes with some people, they can not have available money for investment regularly on exactly weekly or monthly basis and they don't even have to double their input money if they skip a last month (don't have money for DCA last month). They can change from weekly to monthly then back to weekly, depends on their financial status and available money for investment.
When you try to time your buys, then you are only trying to time the markets. When try to time the markets, the price is the time. If you are that smart, sure go time the markets. DCA is for the people who dont know how to do it.
I agree that timing the market is not actually good but if you know what you are doing, you can do it and it is still DCA but it is applicable for more experienced and skillful investors.
For newbies, yes, Traditional DCA is best.