You can technically do it like this and twist the strategy in whatever way you want, but the main purpose of DCA is to just buy an equal amount every time, to eliminate the psychological/emotional factor of markets. Changing the amounts every time kind of defeats the purpose of doing DCA.
These are nuances. What is classically called DCA, pure DCA, would be buying the same quantities at the same time intervals. If it is not so exact but we can buy more depending on the available money or we vary the intervals depending on the availability (and we buy an extra amount for example on the day we receive a bonus) it would already be a variant of DCA, which can have more volatility.
With pure DCA in an asset that appreciates over the long term what we do is to dampen volatility and as we move away from the same intervals and equal amounts we risk having more volatility.