yup pretty much, unless using decryptors stick to single run BPCs as more runs gives 0 benefit, if using decryptor then go with max run
decryptors can be the most expensive part of the invention process, unless you find them probing, i personally made a fortune selling "found" decryptors, and used quite a few for myself too.
i personally wouldnt go to the expense of using decryptors unless my science skills for the invention were all 5 or i had loads of money, failure to invent with decryption hurts the wallet.