No, steaming time does not depend on your technique. Unless you are lifting the steam wand out of the milk and splashing it everywhere, heat transfer is happening consistently. This means the time it takes to reach a specific temperature remains constant regardless of the technique you use.
The Breville features a quite slow steaming process, taking about 55 to 60 seconds to steam milk for a latte. The benefit of this slower speed is that it provides a very gentle steam, allowing the milk to churn slowly and make fine microfoam with very little effort or skill. The Decent machine historically steamed in the 46 to 48-second range, but newer firmware updates have made it 25% to 33% faster, bringing the time down to the 32 to 35-second range.
As the steam power and heating speeds increase, the process becomes more violent, which requires more technique and skill from the barista to successfully texture fine microfoam. To help mitigate this, the DE1 comes standard with a single-hole steam tip. Multi-hole tips can easily create unwanted large bubbles if even one hole accidentally lifts above the surface of the milk, making them much harder to control.
Decent has been collaborating with Zubing, the inventor of the Force Tamper, to develop a new "blade" steam wand tip featuring a single slot. This design keeps the steam spraying in a narrow, straight line, but the wider slot cut reduces the overall violence of the steam. This allows users to easily create perfect microfoam at fast speeds, mimicking the forgiveness of a slower steam wand.
In milk steaming, there is always a trade-off between steam dryness and texturing difficulty. Dynamic, dry steam is more violent and requires more talent to master, but it yields the fastest results with the least amount of water dilution. Conversely, less violent options—like the upcoming blade tip or Decent's optional three-hole tip—make creating perfect foam much easier, but because they operate under less pressure, the steam is slightly wetter and will introduce a small amount of extra dilution to the milk.