Best and highest offer due on a Thursday

[Jacob Mitchell]

My question: Are banks firm when they state Best and final offers are due by Thursday at 5pm or will they continue to accept offers throughout the weekend?

My Situation: I submitted an offer on a rehab REO property that is in a highly desirable and competitive area. After a market analysis my agent and I determined the property's ARV is worth twice as much as the list price.

The property was listed on the MLS on Tuesday.

I submitted my offer on Wednesday. 

End of day Wednesday the property had over 1000 views on Zillow and 50 favorites (popular for this area).    

On Thursday at 3pm the listing agent stated he had multiple offers and asked for Best and Highest by 5pm that night. I increased my offer. 

Today is Friday and I was hoping to hear back on the banks decision but the listing agent informed us that we will not have an answer until Tuesday. 

I understand that the nature of bank deals is that they are slow but it seemed like they wanted to close this one fast by asking for best and highest after only two days on a Thursday.