TTC like any other system can defer or cancel options when it's in their best interest. They can go else where for those options.
Based on TTC going out for an RFI and a meeting schedule in Octobers with suppliers, TTC is saying they may defer looking at the option pertaining to the contract until they know what the markets looks like as well what time frame they maybe looking for delivery. They will also have an idea what cost they maybe looking at for these cars. Once TTC has all this info, only then will they say which way they want to go to the point they may say bye bye BBD and we will see you about 10 years or so down the road bidding on our contracts then.
Since Siemens has the lion share of new cars in NA, they want to add TTC to that list of buyer for their cars as well keep the market to themselves. The 3-7 cars orders can be handle by small suppliers in the US at this time, but will not stop Siemens bidding on them.
I thought I was bad for posting, but yours took some doing to understand what you are saying.