The amount a state can order from the manufacturers is set by a chart that lists the max doses each state can order week by week. The amount a state can order is determined by its relative population.
If there is less now than before, it's because of production. The manufacturers originally had a stockpile in anticipation of getting approval. Once they go through that stockpile, they have to dial back to what's being produced week by week.
There has been no formulated plan under the Biden administration that has changed what was happening previously, as per their assertion that they have to come up with a plan, which means that right now, there is still the inherited 'no plan.'
Remember that initially most states weren't able to keep up with doses given because of their unpreparedness. Now that they've ramped up dose distribution and can handle more doses... the stockpile is gone, despite the Trump administration's director of HHS saying there was still a stockpile to let loose just a week ago.
If the Trump administration was keeping on top of things, they would have instead told the states that they've gone through the stockpile, and so be prepared for less shipments per week. But states instead ramped up distribution and reservations for doses.
May I remind you how unlikely the new administration, which is only six days old, can be held accountable for the doses that arrived last week and this upcoming week.