High folks
Apparently they have not added any additional ceremonies for May whereas Mississauga has already added many for May 2018. It is for sure that Scarborough does not have citizenship judge and mostly relying on the availability of judges from other centers . Unless additional ceremonies are available for May, it will be difficult to send more invites. High volume of applicants with no sources available builds up the queue. Hoping for the best
(regarding the bolded comment)
There is simply no evidence of this. They appear to regularly schedule a Wednesday evening and then three Saturday ceremonies. Four sessions a week means they are processing a max of 360 applicants per week, based on 90 applicants per session as has been reported in this forum. This is in addition to the occasional Toronto ceremonies, which at times have greater capacity. (In the hundreds per ceremony.)
Just because the ceremonies are not published right away doesn't mean they aren't scheduled and planned. Mississauga has 6 regularly scheduled sessions per week. I don't recall seeing any postings as to how many are seated for their sessions, but it could simply mean that Mississauga takes on more casework than Scarborough, which would explain, perhaps, why some get transferred to Scarborough. I'd be willing to bet that these two offices share the same judge(s).