Hello Stephanie,
You started the same thread in January, and it appears that a number of people responded. I assume you have tried it out by now. What are your thoughts about the app?
Are you in some way affiliated with the app or the app developer?
I think rogdcam provided very useful thoughts in the January thread - mostly about limitations and caveats.
I have not used the app, but since this app appears geared toward the novice, it seems to be possibly useful to provide guidance to the country and type of issue, but should be used for an identification starting point, and not at all for valuation. The user should always next go to a good reference catalog like Scott, Gibbons, Michel, etc. depending upon the country.
Valuation is a very vague and potentially misused term. Valuation depends upon:
1. Correct exact identification. As mentioned, there are many features (perforation, design type, design size, color, tagging, watermark, cancellation type, etc.) which this app may not be able to identify.
2. Condition. Also as mentioned, there may be one or more flaws. For example, thin spots, tears, creases, pulled perforations, re-gumming, etc.
3. Centering. Stamp centering is important for valuation.
4. Purpose of valuation. Want to sell? Most likely a person will not pay close to the "catalog" or "value" price listed. Depending upon scarcity, demand, condition, centering, the realistic selling price may be 50%, 5%, 200%, or whatever. You can check
ebay or other venues to check for "sold" prices (in other words, check the prices realized for items that have actually sold).
So, in summary, value/price is not useful, and may be misleading.