[Avodah] Fwd: Tefillin d'Rabbenu Tam

[shalomyitz at comcast.net]

In this shiur: http://www.yutorah.org/lectures/lecture.cfm/796382/Shay_Schachter/Kissing_the_Mezuza-_Tefillin-_Tzizis_and_More-_ 
Rabbi Shay Schachter discusses, among other things, the Gemora (Brachos 14b) that 
one who recites Shema without wearing tefillin is an eid sheker. 

He goes on to discuss that people who put on Rabbenu Tam tefillin are careful to say 
Shema and vHaya im Shemoa when they put them on. He also relates a story (which acc. 
to him may not be true) that the Chasam Sofer davka did NOT say Shema when he put on 
Rabbenu Tam tefillin. (All of this is under the assumption that you put on the Rabbenu 
Tam tefillin after you've already removed the Rashi tefillin, not at the same time). 

I have some questions about this. Under the first minhag: Although the gemora says 
don't say shema without tefillin, that's not the same as don't wear tefillin without shema. 
So, what is the need for saying shema when you put on Rabbenu Tam tefillin. 

The second minhag (i.e., the Chasam Sofer's supposedly being careful not to say Shema while 
wearing Rabbenu Tam tefillin) initially made sense to me: Since we hold that Rashi tefillin 
are right, then when we put on the Rabbenu Tam tefillin, if we say shema, we are 
saying shema without tefillin (the Rabbenu Tam tefillin aren't really tefillin). 

But, the more I thought about it, it made less sense. Those who put on Rabbenu Tam tefillin 
presumably do so because there is a safek about which is right. (This seems to be implied in 
the Mishna Berurah 34(8): "ECHAD mehem pasul" -- but we don't know which, and therefore 
when we put on both we aren't over bal tosif). Therefore, if you put on Rashi when you are 
saying the Shema initially, and then put on Rabbenu Tam later, you may have said the Shema without 
tefillin the first time -- and presumably we are all doing that every day. Would it be 
better to 'make up' for that by saying Shema while wearing the Rabbenu Tam tefillin -- or, 
is it better to not risk ANOTHER violation... i.e., as I said above, it doesn't seem we have 
to say Shema whenever we wear tefillin. So, if we put on the Rabbenu Tam tefillin, and they 
are the real tefillin, then we don't need to say Shema; and moreover, if they AREN'T really tefillin, 
then if we say the Shema we are eidim shekirim. 

(R'SS mentions in passing that "we are only putting on Rabbenu Tam tefillin for the kavod of Rabbenu Tam. 
But, if that were the case -- and it wasn't because of a safek -- then the MB, as cited above, would imply 
that we ARE over bal tosif). 

Something just doesn't seem right to me about all this....