i have asked a million people this question but i will ask it again just to reassure meself

currently i got a manual boost controller in me car and runnin 1.1bar and it will boost to 1.1 for 500 revs then drop to 1 bar then past the 5500 mark it will further drop to .9 bar........ hmmm.... its not somethin wrong just askin is this a case of the turbo (td04L) not able to hold the boost or crappppppppy mbc??

thanks dudes
mark