LM3881: Lower limit of pullup resistance

Hi Support Team,

My customer is thinking about the pullup resistors of FLAG1, FLAG2 and FLAG3. The datasheet says that the resistors of 100 kOhm are recommended. They would like to reduce the resistance value and know the lower limit of pullup resistances. In their simulation with PSpice, LM3880 with pullup resistors of 1 kOhm  works well.

Could you please tell me the lower limit of pullup resistances   and   the points of attention when they use the pullup resistors less than 100 kOhm?

Thank  you for your help.