No particular reason. I wrote them as
self.convtransposed64 = nn.ConvTranspose2d(in_channels=64,out_channels=64,kernel_size=(2,2), stride=2)
self.convtransposed128 = nn.ConvTranspose2d(in_channels=128,out_channels=128,kernel_size=(2,2), stride=2)

In  init and it worked. Thank you!