Hi Danny,
Yep, I've seen the reference to lacquer thinner on Tamiya's page before. Actually, I believe I first heard of it being an alternative thinner some time in the late 80's, so it's not a new thing.
EBergerud
(Someone on Promodeller found a citation from the Tamiya page confirming that their lacquer thinner is the better choice.)
The way I read the product information on Tamiya's paint page, it (Tamiya lacquer thinner) merely seems to be mentioned as an alternative thinner with an attribution to (unspecified) "expert modelers" finding it gives a harder shell. I don't see that as any confirmation, suggestion or endorsement that lacquer thinner is a better choice. I will say that as mentioned above, the lacquer thinner seems to afford a longer dry-time compared to alcohol/alcohol based thinners, reducing the possibility of dusting or pebbling. However this can also be achieved by using a retarder, painting at lower air pressure and spraying closer to the surface being painted. It comes down to individual technique and methodology.
Hogzilla
the Modulation Technique sounds the so called "correct method" to paint a motor vehicle I was taught, which is; 2 transparent coats, 1 or 2 cover coats with a wait in between each coat to allow it to get tacky for good adhesion of the next coat to prevent runs and and lastly the final or ("money coat"). I have be using that method since I first bought my first airbrush (an unbreakable Badger 350) in the summer of 1977. I've found thinning Humbrol & Testor paints in the area of 1 part paint to 2 parts thinner at perhaps 10 to 15 psi as a starting point for transparent coats and adding paint the traditional 1:4 ratio thinning mix of 3 or 4 drops at a time for each coat until the final money coat is achieved. This is a work around to the coarse atomization of external mix airbrushes and gives a nice scale-like paint job.
Indeed, the best way to apply any sort of paint is to use mulripe thin applications, building up the required colour depth, and is my own personal preference, sometimes making 4-5 passes or more to achieve the desired coverage. Use of very thin coats also reduces the tendency of the paint to "soften" detail when applied too heavily.
However, the Modulation Technique is more an effect, a variation on "post shading" rather than a basic application technique. Colour Modulation, as I understand it, introduces varying shades of the base colour to create the appearance of shadows on a model. For this to be convincing, the transitions in shade have to be subtle, hence the need for very thin applications of near translucent paint.
Hogzilla
In early 1969 I was at MCRD - San Diego as a Marine recruit and one of my drill instructors said something to vugar to put here about how to increase survival odds in Vietnam. A translation would be "if you start to believe your any kind of expert in anything your survival odd go down and you might just die young - if your an observant learner your survival odd go up, then he ordered us to be observant learners for the rest of our &%#@$ing lives. So Please don't counsider anything I post as the final word on anything because I am no expert in anything and don't plan on becoming an expert eather.
Good advice indeed 
I'm not claiming to be an expert either, I'm neither an industrial chemist nor a paint technologist, just someone who's been using Tamiya acrylic paints since they first came on the market in the early 80's. In fact, the whole lacquer thinner thing is fairly new to me, having only tried it in the last month or so. Traditionally, I've used (and still use) denatured alcohol as my thinner of choice, but I can see some advantages in the slower drying afforded by the use of laxquer thinner, particularly when using gloss paints.