Platinum blonde bleaching - breakage?

Thanks for the advice.  I've been using a good leave-in conditioner, but my stylist told me to only use deep conditioners containing protein as one of the main ingredients only twice a month.  She says too much protein can actually increase breakage.  I just had my hair done today & what she's going to do is touch up my roots & then pull the bleach down the hair about 5 minutes before shampooing.  She said after doing this a few times my whole head will be the color I want it. 

My hair (naturally level 7 ash blonde) has been through a lot in the last year.  It was originally hilighted blonde, then I dyed it level 2 dark brown.  I kept it that color for about six months, and since then I've gradually been lightening it with weaves.  It's taken me three months and I'm at a light neutral blonde color, but I want to be PLATINUM!  I was thinking I'd just do a bleach out, so I went to a consultation with a new stylist and she told me I'd have to sign a waiver in order to do this because she was really worried that my hair would suffer severe breakage.  She told me my hair didn't look or feel damaged, but it had very little elasticity.  I told her that I'd completely bleached my hair out before & it didn't break, but she told me this still didn't rule out severe breakage this time around.  So now I'm scared to bleach it all.  Any advice???  I've been making sure not to heat style my hair & I've been conditioning like CRAZY!  Let me know if you have any good advice for this topic.  It's been 6 weeks since I've processed my hair from roots to ends.