KC: If it says Thomas in the middle of the 2 turns it is supposedly made in 1908?!??!To be precise items with this mark were made between 1908 and 1939. Just as with the Rosenthal marks Thomas used that peculiar 'dot notation' to indicate year of production, however unlike the partially complete Rosenthal sheet I have never seen one for Thomas/Marktredwitz. [Guess]: It *may* be similar to the Rosenthal art department date sheet - that's just plain deduction as all other subsidiaries also match the art department layout instead of the main factory. I've never checked Thomas on that, though (time issue).
tubularjuan:The mark type gives us a date span of 31 years; decoration style and body type are also plausible for a pre-1920 item. So far we have cornered that nicely: you have the manufacturer (Porzellanfabrik Thomas, town of Marktredwitz in Bavaria), a maximal ('mark run') period (1908-1939) and you have a good hint (likely pre-1920). Those are all valid and pulled up without the text underneath - looking at that, 1912 as date for that item appears perfectly possible.
Main question was if these additions in any way influence value. Normally not because these notes are not company additions - notes like on your item may be interesting for some family member and/or research purposes but otherwise such texts are irrelevant. Of course in family cases the normal sentimental family value may be higher in comparison to untexted items as it's in a sense a commemorative item. Which explains a few auctions were people out of such families were shocked to learn their treasured items were worth just the normal street price for an un-texted item. Anyway, I always take a neutral approach - as you could see: facts first.
Standalone note on why many people disregard these notes or may even get a bit agitated:
Problems with such text notes nearly always have to do with plausability and/or credibility. Some folks freak out or accuse owners/sellers without checking facts first ... why? You see, years ago it was only the faked 'manufacturer / decorator test' item or a commented trial firing relic or whatever. That already was quite a bother but then came eBay and suddenly every junkaholic tried to make money by bullsh*tting others at all costs. Guess how many people out there tried (and are trying) to sell 'old' items with some 'old' text underneath? Like the definitive 1950's German Sammeltasse with handwritten '1890 vienna' comment, for example. Thus, every out-of-the-norm item is per definition claimed to be suspicious. I find such items (valid or not) highly entertaining and interesting, many others are either not interested (anymore) or go ballistic (probably because they got cheated before). But it would be bad advice if I would not mention that there *are* people out there that really collect such items without making a fuss (probably nerds like myself only with money, lol!).
Hope that helps somewhat