Couple questions, When you say it flowered over the winter, did it ever go into dormancy? Almost all of my leaves died back this winter and flowering was the last thing it was debating. Come around the end of Feb it started shooting out leaves like it never stopped. Besides the lighting becoming more intense, the constant house temp might have thrown it off.
What size pot are you growing it in? If it is rather shallow then root rot can be an issue. One cm is a lot to a 3 inch tall pot. If a larger pot, and under normal circumstances, you might be able to actually increase your watering. Mine is growing outside in a 10" pot (height) with a 4" "deep" saucer (also have filiformis and capensis in there). I typically top water about every other day until it fills the 4" saucer. I make sure to give it good flooding.
For your jaumavensis don't worry about "too much" lighting. This quote from Partrat over at pinguicula.org always sticks out in my head when I hear about low lighting levels:
I read an article on cactus cultivation where it was indicated that luminosity in Mexico has nothing to do with what we can imagine. Mexico is a very sunny country and, even if the Pinguicula grow under the shade of grass or shrubs, they received more light than in France with direct sun, with some measure of course. Nevertheless, I do not advise to grow your plants in full sun but under a light shading cloth or under "dirty" glass.
I personally have mine under a 4x48 T5HO 6500K fixture at the moment. I had to move some stuff around so had to take down my 100W 2700K CFL. I am still getting decent coloring with the 6500's but throwing an extra 2700K bulb or two makes them color up like crazy.
Something a lot of people neglect on pings too is humidity. You got to remember these things do live in mountains and while actual rainfall may be low they expect that night time spike. If you can keep the soil just barely moist but humidity in the 60's-80's you will see a difference in size.
Finally, if your soil mix allows (i.e. at least a 1:7-1:8 ratio of peat) it makes life so much easier seeding the pot with springtails. I still occasionally use a ground blood worm/water paste on a leaf or two but watching the pings actually catch their own prey is pretty rewarding. I actually saw my smallest jaumavensis catch one just a couple days ago. Look slightly underneath and to the right of the jaum in the bottom right hand corner (it's kind of hard to see). The elongated brown speck is a springtail literally the size of one of the ping's leaves. I was proud of the little guy for taking on such a large beast!