Your VX-1 is not the same quality of glass as the VX-3 due to the coatings on the lenses,,, where the VX-3 has the additional coatings and should be providing better light transmission under low light conditions. And you need to compare scopes of similar qualities to get accurate results. If they are not, as suggested, there may be an issue with your scope requiring warranty service.
The Leupold Vx-3 is a quality scope and should provide better light transmission than many other makes and models.
In an informal side by side field comparisons of many of the then makes and models of scopes (mid 2000's), under low light conditions, the best experienced by myself (20/20 vision set for 7mm exit pupil) and my mentor (a retired research scientist, set for 5mm exit pupil), the best low light scopes were Kahles and then Swarovski, with Leupold VX-3 (their top model at the time) being right there with Zeiss and Nightforce. An interesting note was that the Kahles and Swarovski gave about a 5 minute advantage over the next level of scopes (Leupold, Zeiss and Nightforce). The advantage of these over the next level of scopes was about 15 minutes. The test medium was the able to clearly read various sizes of writing on targets set at various ranges on the 400 yard range during bright sunlight, shadow and twilight conditions. As not all scope had adjustable paralax, those that did were set for 150 yards (IIRC), to match the same as those that did not, and were set to that range as default by the manufacturer.
A valid point is that you are not providing examples of what power setting you are looking through your scope at during dusk. This will impact your exit pupil( the amount of light that the scope will pass through the scope to your retina).
The average healthy young person's (approx. 20 years of age) retina will expand to a maximum of 7mm, and cannot accept any more light than this from the scope. As we age, our retina muscles wear and cannot open as fully, therefore limiting the amount of light that the retina can accept from the scope, thereby diminishing how bright the image we see is. By about the age of 50, the average person's retina can only expand to approx. 5mm. And gets continually smaller as you age from there. Obviously, if you have eye issues, your retina may be reacting differently than this
A 40 mm objective lense at 9 power will have a (40 / 9 =) 4.44mm exit pupil. At 8 power, the exit pupil is 5mm. At approx 5.7 power the exit pupil will be 7mm.
Dependent upon your age and size of your retina under low light conditions, you are best to set your scopes power setting to optimize it so that the most light gets to your retina through the scope, giving you the brightest image possible through the scope. (You cannot compare this to what your eyes are taking in when not looking though the scope). Then you will be able to make a more accurate assessment of your scopes ability to transmit light to your retina.
Then you will know what maximum setting to set your scope to when hunting at first or last light so that you have the best light transmission and image of your target to aid in placing your shot accurately on target under those light conditions.