Hi tyfattori. If I understand your post aright, I think you misunderstand what an hydrometer reading tells you. Knowing the specific gravity after the yeast has been actively fermenting tells you nothing whatsoever about the "weakness" or "strength" of the wine. It tells you ONLY how much residual sugar remains. And the amount remaining has nothing to do with how much fermentable sugar was in the wine before you pitched the yeast. That means your must (the juice before you pitch the yeast) could have had a specific gravity of 1.050, or 1.100 or 1.150 or any other number (and these three gravities COULD ferment a wine giving you an ABV of about 6.5%, 13%, or 19% . So is your wine "weak". Well, I don't know what you mean by "weak" and even if I did I would not know what the ABV of your wine might be since you only advise us of the amount of residual sugar in your wine...
BUT the amount of sugar in your wine seems to have increased since you racked (moved) your wine. If it was at .990 one day and then at a later date it increased to 1.010 there is now about 8 oz of sugar in each gallon that was not there before. Now the cause of that increase could be one of four things -
1. magic
2. a misreading of your hydrometer (reporter's error)
3. an inaccurate and unreliable hydrometer (malfunctioning tools)
4. a third party who added more sugar to your wine but who failed to inform you.
Me? I would discount reasons 1 and 4. Reason 3 can be tested by simply measuring the gravity of distilled water (it should be 1.000) and then measuring the gravity of distilled water to which you have added 2 oz of sugar and which the volume is precisely 1 pint. The gravity should be 1.040. If it is then reason 3 seems unlikely... which leaves only.. But as I say, I may have misunderstood your post.