Why IvIg was given twice in a row?

Hi Everyone
I am still on IvIg for the very low plts. Everytime I had IvIg infusion my plts went way too high like 951 k & within 20 days it dropped to 6k ...I got approval for Rituxan & hoping to get it soon. Anyways I am just curious to know that when i got IvIg in past, It was only one infusion , But april 25th 2011 when my plts were 9k I had ivig once on 25th & the next one on 26th. I am just curious to know if there is any reason my hema choose to give me 2 treatments of ivig in a row rather than one?
Any ideas?

Thanks
Splenectomy march 2007 (Unsucessfull)
Rituxan(last tratment was on May 2007, Remission till January 2011)
February 14, 2011- 20k(treated with prednisone for 2 wks)
February 25, 2011- 989k
March 04, 2011 - 650k
March 07,2011 - 141k
March 08, 2011- 27k
March 09, 2011- 14 K (Treated with IvIg 1st shot)
March 14, 2011- Cbc was not done ( 2nd shot of IvIg)
March 22, 2011- 951K
March 29, 2011- 450 K
April 04, 2011- 6 K
April 05, 2011- 0k (1 shot of IvIg)
Still on IvIg

My Hemo explained that two doses is the standard clinical dose, though up until now I have only received a single dose at a time because this was effective.
This has changed for me, as a single dose now has dramatically reduced efficacy and I will be having the standard (double) dose next time (shortly).
My Hemo explained that there may be some value in placing a day or two in between the doses so my kidneys have a chance to process it and they don't get "gummed up" (his words).

It's all physician preference. Some people have had it five days in a row. I'd think it would also depend on dose and speed at which it is given.