You mean it's 28% transmissivity? That's a pretty normal value for medium tint. Where did you get that figure, from Lotus directly? Or from a dealer?
In terms of perceived darkening compared to non-tinted glass, 35% is "light", 20% is "medium dark", 5% is "limo dark". I have 20% on my BMW and you can still see pretty easily into the car in daylight, but it makes the greenhouse of the car appear visually more as one solid piece rather than as a void space between the metal of the car's A, B, and C pillars.
I found a tool online that lets you visualize the effect, and it's pretty accurate compared to my own experience.
https://www.windowtintinginlv.com/percentages-of-window-tint.html