"However, I wonder why SIAF cannot change its standard credit time from 90 says to 60 or even 30 going forward. Over a quarter this would amount to a substantial cash flow benefit, stalling the need for cap ex from new shares; hopefully, until it isn't needed at all."
That's presumably because economic relationships are not yet disembodied as in the West; they are still to some extent personal relationships between two people requiring much more flexibility, more give-and-take than is our custom. Too push too far could cause permanent loss of that relationship, not just temporary severance of a customer.