Assuming IN operator is supported in databaseManager.addTableFilterParam and so I do not need a previous Select statement, I tried the following :
var success = databaseManager.addTableFilterParam('cotizaciones', 'clientes', 'provincia', 'IN', (1,6), 'listaPcias')
and also
var success = databaseManager.addTableFilterParam('cotizaciones', 'clientes', 'provincia', 'IN', (6,1), 'listaPcias')
in both cases it shows the records that match the last parameter mentioned in the IN list (in the first example it shows records in which provincia is = 6; in teh second, those in wich provincia is = 1).
I did not find anything in the documentation to clarify how to properly write the IN list.
I am using 4.1 beta 4 .