Amritvela is actually necessary. If we have any confusion then we should first ask Guru Sahib. Any person can be wrong as Guru Sahib says,
ਭੁਲਣ ਅੰਦਰਿ ਸਭੁ ਕੋ ਅਭੁਲੁ ਗੁਰੂ ਕਰਤਾਰੁ ॥
Everyone makes mistakes; only the Guru and the Creator are infallible.
but Guru Sahib cannot be wrong.
For Amritvela we should read bani of Guru Ramdas Sahib,
ਗੁਰ ਸਤਿਗੁਰ ਕਾ ਜੋ ਸਿਖੁ ਅਖਾਏ ਸੁ ਭਲਕੇ ਉਠਿ ਹਰਿ ਨਾਮੁ ਧਿਆਵੈ ॥
One who calls himself a Sikh of the Guru the True Guru shall rise in the early morning hours and meditate on the Lord's Name.
ਉਦਮੁ ਕਰੇ ਭਲਕੇ ਪਰਭਾਤੀ ਇਸਨਾਨੁ ਕਰੇ ਅੰਮ੍ਰਿਤ ਸਰਿ ਨਾਵੈ ॥
Upon arising early in the morning, he is to bathe and cleanse himself in the pool of nectar.
This Shabad confirms that we have to do Amritvela. Also, Bhai Gurdas Ji has written daily conduct of Gurmukh.
ਗੁਰਸਿਖ ਭਲਕੇ ਉਠ ਕਰਿ ਅੰਮ੍ਰਿਤ ਵੇਲੇ ਸਰੁ ਨ੍ਹਾਵੰਦਾ।
The Gurmukh getting up in ambrosial hours of the early morning takes bath in the sacred tank.
ਗੁਰੁ ਕੈ ਬਚਨ ਉਚਾਰਿ ਕੈ ਧ੍ਰਮਸਾਲਾ ਦੀ ਸੁਰਤਿ ਕਰੰਦਾ।
Reciting the holy hymns of the Guru, he moves towards Gurudwara, the central place for Sikh.
When Gurbani confirmed that we have to do Amritvela then we shouldn't listen to any person for confirmation of doing or not.
