We find the petition impressed with merit. Viewed in light of the fact that Esguerra's contract of employment was executed on 9 May 2003, CSMSI correctly faults the CA for applying POEA Memorandum Circular No. 055-96 instead of the 2000 POEA-SEC which took effect on 25 June 2000. Deemed written in the seafarer's contract of employment,[20] the 2000 POEA-SEC - like its predecessor - was designed primarily for the protection and benefit of Filipino seamen in the pursuit of their employment on board ocean-going vessels.[21] Anent a seafarer's entitlement to compensation and benefits for injury and illness, Section 20-B (3) thereof provides as follows: "Section 20-B.Compensation and Benefits for Injury and Illness. -xxxx 3. Upon sign-off from the vessel for medical treatment, the seafarer is entitled to sickness allowance equivalent to his basic wage until he is declared fit to work or the degree of permanent disability has been assessed by the company-designated physician, but in no case shall this period exceed one hundred twenty (120) days.E For this purpose, the seafarer shall submit himself to a post-employment medical examination by a company-designated physician within three working days upon his return except when he is physically incapacitated to do so, in which case, a written notice to the agency within the same period is deemed as compliance. Failure of the seafarer to comply with the mandatory reporting requirement shall result in his forfeiture of the right to claim the above benefits. If a doctor appointed by the seafarer disagrees with the assessment, a third doctor may be agreed jointly between the employer and the seafarer. The third doctor's decision shall be final and binding on both parties. (Emphasis added.) The foregoing provision has been interpreted to mean that it is the company-designated physician who is entrusted with the task of assessing the seaman's disability,[22] whether total or partial, due to either injury or illness, during the term of the latter's employment.[23] Concededly, this does not mean that the assessment of said physician is final, binding or conclusive on the claimant, the labor tribunal or the courts.[24] Should he be so minded, the seafarer has the prerogative to request a second opinion and to consult a physician of his choice[25] regarding his ailment or injury, in which case the medical report issued by the latter shall be evaluated by the labor tribunal and the court, based on its inherent merit.[26] For the seaman's claim to prosper, however, it is mandatory that he should be examined by a companydesignated physician within three days from his repatriation.[27] Failure to comply with this mandatory reporting requirement without justifiable cause shall result in forfeiture of the right to claim the compensation and disability benefits provided under the POEA-SEC.[28] There is no dispute regarding the fact that Esguerra had altogether failed to comply with the abovediscussed mandatory reporting requirement. Beyond his bare assertion, however, that CSMSI "never gave him referrals to continue his medications as recommended by the foreign doctor" despite his call on 8 July 2003 "to inform them that he will report the next day in order to submit his medical evaluation abroad," Esguerra did not present any evidence to prove justification for his inability to submit himself to a postemployment medical examination by a company-designated physician. If a written notice is required of a seafarer who is physically incapacitated for purposes of compliance with said requirement, we fail to see why a more tangible proof should not likewise be expected of Esguerra who, after his arrival on 7 July 2003, appears to have been well enough to consult with Dr. Vicaldo and Dr. Saguin on 9 July 2003.[29] Indeed, self-serving and unsubstantiated declarations are insufficient to establish a case before quasijudicial bodies where the quantum of evidence required to establish a fact is substantial evidence.[30] Often described as more than a mere scintilla,[31] substantial evidence is such relevant evidence as a reasonable mind might accept as adequate to support a conclusion, even if other equally reasonable minds might conceivably opine otherwise.[32] To our mind, Esguerra's compliance with the mandatory reporting requirement under the POEA-SEC was made even more imperative by the fact that his repatriation for medical reasons was categorically