Usually most of these asian layouts make some sense. To say more about it, it is necessary to know whether it is a blow only (most probably) or a blow and draw. The last note of the upper reed plate is not readable clearly. Most probably it means "A#/Bb" - that would make more sense), but it could mean "G#/Ab" as well. (I could not find a better picture or a layout sheet. Neither I could find any information about the measurements and the weight of the instrument.)
If it were a blow and draw, this layout were similar to some asian chromatic tremolo harmonicas (f.expl. Suzuki) or chromatics without slide (Tombo) which come in various layout systems with more or less differences among each others. These have reed plates with alternating direction of the air flow (blow - draw - blow - draw etc), like many slide chromatics (f.expl. Hohner CX-12). With the tremolos the order of the layout has to be thought in quadrants. This allows a correct splitting to play single notes. (* see footnote below) That gives a playable layout similar to a solo tuning or a mixture of solo tuning and Richter, depending on the direction of the air flow.
But I do not know, if Easttop makes bass harmonicas with blow and draw at all. And most of the slideless chroms have upper and lower row of holes offset, whilst the easttop bass apparently has the holes straightly above each other, like several of the the tremolos as well.
This is the layout as I could read it – just only the holes:
I could not find any information about the direction of air flow (blow only or blow and draw).
Edit: As I studied the layout closely once more, I found out that it is definitely not fully chromatic. In the low octave is missing the D#/Eb. (At least nobody did claim this. Its name is "Melody Bass" - by means as it seems.) The multiple inversions of the order of the notes and some strange doublings - more than once in an octave - remind me to some of the known (and here reported) asian tuning systems. But it is definitely different from all of them, and I do not get its intention, especially not without knowing the direction of the reeds (Blow / draw). For an only blow instrument it seems to me quite weird up till now.
By the way - talking about the quality of Easttop bass harmonicas: In 2016 at the international music trade fair in Frankfurt/Main, DE I played a similar instrument on the Easttop stall for about 15 minutes. Its price was 70 Euros (cash to take away at once, usually comes shipment and tax on top). That was about a sixth compared to a similar instrument made by Tombo. The quality was that crappy, that I did not buy it at this very low price. It was very very airy and required far too much breath, and quite low in volume too. A killing argument for a bass harmonica. It would have been just like throwing the money out of the window. If Easttop has not improved the quality of its chromatic bass harmonicas by a multiple within the last two years, I would not recommend to buy any of them.
*) Just look at the pictures and diagrammes, if you can not read German.
For the Suzuki SU-21-H and Baritone (tremolo) see here:
https://www.harpforum.de/phpbb/viewtopi ... 30#p111030
For German style octave harmonicas look here:
https://www.harpforum.de/phpbb/viewtopi ... 25&t=13634
For Tombo S-50 and Violin Scale 1577 (slideless chromatic) in comparison to standard chromatics look here:
https://www.harpforum.de/phpbb/viewtopi ... 25&t=13621
A comparison of different layouts of German style octave harmonicas:
I do not know if any of this is comparable to the layout of the Easttop bass. And anything depends on, whether it is blow only or blow and draw.
I just linked it here to illustrate what I mean with the quadrants like the Suzuki Humming and Baritone have it. To some degree the octave harps show a similar system, where each quadrant of four holes beside and above each other can be counted as "one hole". The description of the Hohner octave harps (in the second link) with its "10 holes" containing 4 quarters each shows this very good. (Each "quarter" is a channel with only one reed for itself. Together they contain the blow note and the draw note of a single hole / channel of an e.g. Richter harp, both octavated.) The layout of the Suzuki tremolos follow a similar pattern, just with a blow and a draw reed above each other, forming a zig-zag pattern - in difference to the octaves.