I looked for the post Kevin references, which sounded helpful. Although this may not be exactly it, I found a web app from the manufacturer at Energy consumption - calculate yours | Philips Hue US. I tried three values (5%, 50% and 95%) and output was (1.0w, 3.2w and 8.5w) respectively. Reported values have one more decimal place than Sense does, so I agree that rounding is a prime suspect. Thanks for your input, guys!
While searching online, I also ran across a couple other interesting sites. https://atomstar.tweakblogs.net/blog/17888/measuring-calibrated-hue-energy-usage-via-bridge, has a single row of data for the E27 White bulb. The interesting thing here was that the smart bulb uses 0.3w when idle. That comes to 3 cents per month if electricity costs $0.14 per kWh. My indicator bulbs are not powered when the light switch is off, so will not have any idle usage.
The above article explains why there is a curve instead of a line in what Kevin remembers. The focus of that article was comparing lumen output to the brightness setting. This is not the same as energy usage versus brightness setting, which is what I was looking for. However, it was interesting anyway. Hue series bulbs have this curve, taken from the article referenced above:
