Saladette foamed evaporator TD

[nike123]

I recently worked on this equipement:
http://ipelican.com/en/55712
What makes me wander is, what is correct evaporator TD for such type of equipment?
Evaporator is embed in foam on 3 side of compartment and in midlle of doors is small forced air portion of evaporator.
I measured, in perfectly working unit, evaporator TD of 20K. It looks to me little excessive since I expected number of close to 15K.
Any taught on this?
Also, compressor used is for LBP. Is this common practice for "professional" equipment (it is made in China)?

[al]

These things are churned out in the thousands, warranty lasts as long as the wholesaler as one in stock. I've never paid attention to the td i must admit, if it cooled i was happy. I've seen LBP compressors used on bottle coolers from china, bit of a learning curve going on there i think