update field values based on current field values content provider android

I cannot get to update the field values of a content provider as a function of current field values.
For a single column, I try to do

...
 ContentValues values = new ContentValues();
 values.put(TableInOut.INOUT,  TableInOut.INOUT + " + 1"); (*) 
 int numRowsUpdated = getContentResolver().update(TableInOut.CONTENT_URI_PRESENCE, values, "time_details > lastSafeEpoch.toString()", null);
 values.clear();
 ...
 

LogCat says that numRowsUpdated are the expected ones, but there is no update?!
Any ideas please?

(*)
No luck even with these

values.put(TableInOut.INOUT,  "88 + 1"); 
 values.put(TableInOut.INOUT,  "\""  +TableInOut.INOUT + "\"" + " + 1"); 
 

These work, but they do not use current values

values.put(TableInOut.INOUT,  77); 
 values.put(TableInOut.INOUT,  "77"); 
 

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