I wonder if the problem with your cut tulips is air in the stems.

This is a problem with so many cut flowers.

When you get them home,
prepare a deep vase of hot water, (You should just be able to put your hand
into it)
and another vase of Cold water.
Cut about half an inch of the bottom of the stems and plunge them into the
hot water, Watch for very small bubbles coming from the stems, after about
half a minute they should have stopped (if not keep them there till they do
stop) then move them straight into the cold water.
This expands the sap in the stems which pushes out the air that has got into
the stems, then the plunge into cold contracts it and fresh water is drawn
back into the stems. leave them for half an hour or so before you move them
into their final vase.
If you add a packet of cut flower food into the water it can help prolong
the flower life, also with flowers such as Dahlias and others with soft
stems a drip or two of bleach will help stop the water going off.
The best I ever had was a bunch of Gerbera(Transvaal daises), they kept
pumping out air for almost 5 minutes, but they lasted for almost 2 weeks
after treatment.
It is this air lock that causes cut roses to flop at the neck after a day or
so in a vase.

Good luck.
--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk